How to clean RAM slots?

Question

motherboards

We have an asus m4a785-m, the first two RAM slots gradually stopped working normally. The third slot works 50x50, also interruptions. It looks like this: the system starts up, works as soon as you start loading the memory with the processor in the AIDA64 system stability test, and after a minute or two the system freezes, the keyboard does not respond and the hard disk activity stops. Also, the computer sometimes does not start the first time. I tried different bars, constantly changed slots, but now I tried only the third and fourth - it works fine, there are no problems during the test. So these are definitely slots, hardly anything else (in the video card, disks, system and PSU, I'm sure).
It was assumed that some contacts in the first two slots were oxidized, so the memory works intermittently (in the memtest, errors appear only after an hour of testing any memory in the first two slots). And the question arose how to clean them correctly.
PS Already on all the strips, I cleaned the contacts with an eraser, it's not about them.

Answer 1

One of the options: I suspect that the processor socket is "falling off" from the board. You can check it either with the help of the RAM slot tester from Aliexpress, it will have a funny flashing garland when you press the processor socket or try to press down the processor / carefully bend the board and watch for changes in behavior.

Answer 2

Is there really no overheating?