You can cut the clip and save the money, to compensate for the IHS given that is a Socket A cooler you may need to bend the clip as well then it will mount properly. This is why socket 370 coolers are preferred as they will mount with no fuss on pretty much anything P3 and older.

Cut it how? What sort of tool do I need for that? What is an "IHS"? Tried to search online about fitting a socket A cooler (the box actually said it was for A, 7 & 370) on a socket 7 motherboard but it seems it was all about more modern sockets.

IHS is the metal piece ontop of the K6\whatevercpu with all the writing. Its a mini heatsink between the core and your heatsink.
Athlon thunderbirds don't have one and catch on fire with no heatsink attached since they run so hot 🤣 There are actual youtube videos of this 😁 .

I've never removed an IHS from any cpu, its just not worth it for a few degrees, and you risk destroying the cpu, depending on the method used to secure the IHS.
Get another heatsink with more slack in the clip.
Bending it won't likely work with what your describing. I've ran into that problem before.
You don't need a massive sink for a K6, socket5-7 sinks with thumb clips can be found for very cheap still new on ebay\amazon.
http://www.directron.com/fan-p-ss7.html
this one for example which has a delta fan on it, even tho it says foxconn sticker.

Really bad idea, sellotape will dry out and hold nothing ...
You need to find another heatsink or use some thermal-conductive glue and fix it permanently on the cpu .

Thanks everyone. I just bought this one, I hope it will suffice since the k6-300 only outputs 15w max tdp.

Oops, forgot the link:

http://www.ebay.de/itm/371218648197?_trksid=p … 778.m2749.l2649

My 486 uses an AM2 heatsink held on by gravity. As long as I keep the box bottom side down, it is ok