The SCSI and sound card seem alright, but the M/I/O card looks a bit buggered.

There are a few ways to get rid of rust. For bare metal, vinegar is a common household solution, pardon the pun.

For electrical components I suggest dousing, if not bathing the affected section in very very high concentration Isopropyl Alcohol (91% or higher, the higher you go the less residue gets left behind)

You can also try various contact cleaners, but I have never used any myself.

As for if you should buy them is up to you. Do you want them? Even the bad M/I/O card doesn't look too too bad, you could probably get them clean, so long as they are working in the first place.

I/O card is the main thing I am currently looking for since the goldstar I/O card I bought from ebay doesn't seem to be working which I talked about in this thread Problem with my ISA I/O card

I have been wanting to build 386 or 486 system and I have found 3 different motherboards recently. I can't get any of the motherboards to boot because I don't have a working I/O card. There is no guarantee that any of those 3 cards work in the pictures. They are selling them for $8 + $7 for postage. I am sure I could use the ISA sound card too if it works, but the main thing for me is the I/O card which looks rusty. SCSI card would be for the future since I don't have any SCSI hard drives at the moment.

This may be of relevance: Amstrad Adlib Clone: Restoration and Testing

I have a 386 machine that has cards that suffer similar rust damage, the machine seems to have been partially flooded at some point. Everything still works and it seems to be a cosmetic issue but I should take them out and clean the brackets sometime.

I would say it looks alright but to definitely clean the brackets.

I was looking into some rust removal methods online and I was thinking I could try removing the bracket and top com port and try using vinegar+salt solution to remove rust and then use baking soda solution to neutralize any vinegar residue. After that perhaps a scouring pad mentioned in the thread that brassicGamer linker would work on the outside of the printer port and perhaps some deoxit inside the pin holes. If I will buy it, it would be my first attempt to remove rust from something like this.

I wouldn't pay for weathered cards, but if I got them for free...

I'd remove the brackets and remove all the rust using a scotch brite pad (steel wool). Then wash the PCB and bracket with hot water and dish soap making sure to thoroughly dry the part afterwards with compressed air and several hours of sunlight. If it died no big deal, if it survived I got one super clean card.

I don't have good access to free hardware near where I live. Basically my options are to either pay $25-$20 + shipping on ebay for an IO card or try to rescue a card like that.

Baoran wrote:

Someone is selling a bunch of isa cards really cheap. They are very rusty though especially the connectors at the back. Is there any way to remove such rust or should I just forget about it?

Apparently an old Navy trick to remove rust from iron or steel is to smear it with tabasco, the hottest formulation you can find.

Baoran wrote:

I was looking into some rust removal methods online and I was thinking I could try removing the bracket and top com port and try using vinegar+salt solution to remove rust and then use baking soda solution to neutralize any vinegar residue. After that perhaps a scouring pad mentioned in the thread that brassicGamer linker would work on the outside of the printer port and perhaps some deoxit inside the pin holes. If I will buy it, it would be my first attempt to remove rust from something like this.

Doesn't salt cause rust?

gdjacobs wrote:

Apparently an old Navy trick to remove rust from iron or steel is to smear it with tabasco, the hottest formulation you can find.

Tabasco has a lot of vinegar in it.

There are alot of guides online telling to use salt and vinegar as natural rust removal. Most of them talk about using it to remove rust from screws, rusty tools and such though. You are suppose to soak something rusty in salt and vinegar over night and then neutralize the acidic vinegar using baking soda. I wouldn't use it on any electronics, but I was thinking it might work on the rusty bracket and perhaps the top serial port that can be separatad and looks rusty. Not sure if it might be too much for the thin pins in the connector though.

Baoran wrote:

There are alot of guides online telling to use salt and vinegar as natural rust removal. Most of them talk about using it to remove rust from screws, rusty tools and such though. You are suppose to soak something rusty in salt and vinegar over night and then neutralize the acidic vinegar using baking soda. I wouldn't use it on any electronics, but I was thinking it might work on the rusty bracket and perhaps the top serial port that can be separatad and looks rusty. Not sure if it might be too much for the thin pins in the connector though.

The connector is something really cheap to replace so i would not worry about that.

Ampera wrote:

Doesn't salt cause rust? […]
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Baoran wrote:

I was looking into some rust removal methods online and I was thinking I could try removing the bracket and top com port and try using vinegar+salt solution to remove rust and then use baking soda solution to neutralize any vinegar residue. After that perhaps a scouring pad mentioned in the thread that brassicGamer linker would work on the outside of the printer port and perhaps some deoxit inside the pin holes. If I will buy it, it would be my first attempt to remove rust from something like this.

Doesn't salt cause rust?

gdjacobs wrote:

Apparently an old Navy trick to remove rust from iron or steel is to smear it with tabasco, the hottest formulation you can find.

Tabasco has a lot of vinegar in it.

Yup, but it's persistent due to the consistency.