might as well try some other solvents like isopropyl or acetone(nailpolishremover)
and regarding the HF... only if you donate your collection to us after you've died a horrible death due to the exposure to HF.

This will sound weird.... (though probably anyone who has read many of my posts will be like, "Meh, it's not even in the top 10" ) but try making a small puddle of white PVA glue over the scratch, letting it dry completely (Could take 2 days) and then peel it off... I am theorizing that it's grated off stuff stuck in the pores of the ceramic if you like, and "waxing" it like this may pull it out.

Nemo1985 wrote on 2022-03-04, 21:08:

So in the meanwhile I tried stupid consumer grade acids like vinegar and lemon juice, no changes the black markings on the cpu are still there...
We collectors should definitely be able to buy that Hydrofluoric acid 48-50% 😐

Just no even a 5% solution would be too dangerous for the public, there is a reason its restricted and there is no way any government would allow it to be sold unrestricted, its just far too dangerous.

What about putting really good tape on it and pulling it off

Sphere478 wrote on 2022-03-05, 04:50:

What about putting really good tape on it and pulling it off

it could be an idea but if something goes wrong it will take off the markings, I will do a try.

BitWrangler wrote on 2022-03-04, 23:02:

This will sound weird.... (though probably anyone who has read many of my posts will be like, "Meh, it's not even in the top 10" ) but try making a small puddle of white PVA glue over the scratch, letting it dry completely (Could take 2 days) and then peel it off... I am theorizing that it's grated off stuff stuck in the pores of the ceramic if you like, and "waxing" it like this may pull it out.

I'd need to uy it, but I think it may get off to easily? Back at school people were used to put it on the hand, let it dry and peel it off like it was dead skin.

weedeewee wrote on 2022-03-04, 22:22:

might as well try some other solvents like isopropyl or acetone(nailpolishremover)
and regarding the HF... only if you donate your collection to us after you've died a horrible death due to the exposure to HF.

I will consider that :p
The guy is surely in a lab but he uses nytril gloves as protection (and probably some kind of protective gloves and mask), also the quantity of the stuff used is minimal.

I obviously tried the isopropyl and acetone they do nothing in such scratches, they are good to clean stuff like thermal paste though.

That's the actual situation of the cpu:

Nemo1985 wrote on 2022-03-05, 06:26:

it could be an idea but if something goes wrong it will take off the markings, I will do a try. […]
Show full quote

Sphere478 wrote on 2022-03-05, 04:50:

What about putting really good tape on it and pulling it off

it could be an idea but if something goes wrong it will take off the markings, I will do a try.

BitWrangler wrote on 2022-03-04, 23:02:

This will sound weird.... (though probably anyone who has read many of my posts will be like, "Meh, it's not even in the top 10" ) but try making a small puddle of white PVA glue over the scratch, letting it dry completely (Could take 2 days) and then peel it off... I am theorizing that it's grated off stuff stuck in the pores of the ceramic if you like, and "waxing" it like this may pull it out.

I'd need to uy it, but I think it may get off to easily? Back at school people were used to put it on the hand, let it dry and peel it off like it was dead skin.

weedeewee wrote on 2022-03-04, 22:22:

might as well try some other solvents like isopropyl or acetone(nailpolishremover)
and regarding the HF... only if you donate your collection to us after you've died a horrible death due to the exposure to HF.

I will consider that :p
The guy is surely in a lab but he uses nytril gloves as protection (and probably some kind of protective gloves and mask), also the quantity of the stuff used is minimal.

I obviously tried the isopropyl and acetone they do nothing in such scratches, they are good to clean stuff like thermal paste though.

That's the actual situation of the cpu:

photo_2022-03-05_07-23-30.jpg

That chip looks to be in pretty good shape and unless it’s a display piece it might do more damage trying to remove the scratches than to leave it be.

The cpu is not of particular value (that's why I chosen it for this testing), I wanted to get rid of those bad black marks. Apparently they don't go away, I just tried to use an hair product for women which should have 40% of peroxide hydrogen, also use for retro brighting, without particular effect.

Ah, looks like love bites from a heatsink, aluminum, so some form of Sodium Hydroxide, lye, will do the trick. Oven cleaner, drain cleaner are the common household versions. However, it might take a while, need to let it sit on there half an hour plus. Because it's used as paint stripper also, you do not want it get it on the ink though.

BitWrangler wrote on 2022-03-05, 14:24:

Ah, looks like love bites from a heatsink, aluminum, so some form of Sodium Hydroxide, lye, will do the trick. Oven cleaner, drain cleaner are the common household versions. However, it might take a while, need to let it sit on there half an hour plus. Because it's used as paint stripper also, you do not want it get it on the ink though.

Ah, ok, that would be the very opposite of my "some kind of acid" approach. Seems plausible.
The most harmless form might be washing soda.
If you want to go pro, they sell sodium hydroxide in shops for DIY electronics - it's used to develop photo PCBs. Not for kids either, but I survived it before, as a teenager.

Ostensibly, you can also use it to make soap.

BitWrangler wrote on 2022-03-05, 14:24:

Ah, looks like love bites from a heatsink, aluminum, so some form of Sodium Hydroxide, lye, will do the trick. Oven cleaner, drain cleaner are the common household versions. However, it might take a while, need to let it sit on there half an hour plus. Because it's used as paint stripper also, you do not want it get it on the ink though.

Thank you for the tip.

I have an oven cleaner but the only ingredient is non-ionic surfactants 5-15%, I also have the Sodium Hydroxide but i'm pretty sure this will wipe out the paint.
How should I proceed? put some Sodium Hydroxide and then some water? Leave it be for half of an hour? Surely I will use gloves because I already had burning experiences with Sodium Hydroxide mixed with water :p

Update: Wohhhooooo look at this! almost like new!

Now I'm goint to try with this one (just for the sake of science, before and after):

Nemo1985 wrote on 2022-03-05, 16:10:

Now I'm goint to try with this one (just for the sake of science, before and after):
photo_2022-03-05_17-08-17.jpg

Wooo I had one of them AMD DX40s back in the day, so many hours lost to Transport Tycoon on that little box.

Such a loyal machine too, wish I had kept it.

TrashPanda wrote on 2022-03-05, 16:15:

Wooo I had one of them AMD DX40s back in the day, so many hours lost to Transport Tycoon on that little box.

Such a loyal machine too, wish I had kept it.

Yeah unlucky it's quite hard to find a 386 mb with socketed cpu and that didn't had any corrosion damage due to varta batteries. For sure it's not cheap.

See, for every problem there's a solvent. 😂

So that's the result after 1 hour and half:

It seems somewhat better but the stain on the lower part of the cpu is still there, also I don't know if it is noticeable from the picture, but the printing seems a bit cleaned, expecially the DX\

Well it seems there isn't a jack of all trades, maybe the cpu is really scratched?

Anyway I used the oven cleaning product with the non-ionic surfactants 5-15%. Should I try to leave it for the whole night?
Also what if this product get in contact with skin, instructions says it is corrosive and stinging on the skin, what happens if it gets in contact?
I'm asking that to BitWrangler and other expert of chemical stuff.

Non-ionic surfactants are basically harsh detergents. Though if it says it's corrosive it might also have the sodium hydroxide in. Pretty much you wanna rinse it off skin straight away, and if it depleted oils from your skin, put some hand cream on after. Sometimes with messy stuff you might get on your hands, a good glooping of handcream on first is close to a barrier cream, and stops stuff from soaking into a drier skin type. It's not armor though, still need to wash stuff off quick.

i'd be more concerned with it eating away the pins.

BitWrangler wrote on 2022-03-05, 17:59:

Non-ionic surfactants are basically harsh detergents. Though if it says it's corrosive it might also have the sodium hydroxide in. Pretty much you wanna rinse it off skin straight away, and if it depleted oils from your skin, put some hand cream on after. Sometimes with messy stuff you might get on your hands, a good glooping of handcream on first is close to a barrier cream, and stops stuff from soaking into a drier skin type. It's not armor though, still need to wash stuff off quick.

According to the label it doesn't mention the sodium hydroxide, just Non-ionic surfactants. Thank you for the explanation, I will try to let the head of the cpu upside down soaked in that chemical stuff for the night.

weedeewee wrote on 2022-03-05, 18:05:

i'd be more concerned with it eating away the pins.

I don't know about it but the pins are gold or at least gold plated, while the "love bites" are caused from aluminium.

We will see tomorrow I suppose. Noone cpus I used that stuff seems to have pins in bad shape after the treatment.

nope, disaster, all the printing has come off! While scratches are still there...

Nemo1985 wrote on 2022-03-06, 07:13:

nope, disaster, all the printing has come off! While scratches are still there...

Oh no…… dangit!! I’m sorry man.

This brings up another problem us retro guys have.

We need a way to re silk screen old cpus..

Is it possible?