I clean the contatcs with an eraser, and after that use a contact cleaner spray for electronics.
I have NEVER done this as part of any routine cleaning process. If the contacts on the RAM and in the slots are clean to begin with, then once the RAM is properly inserted, you should NEVER have to remove the RAM for cleaning ever again! This is because RAM slots are specifically designed to maintain proper mechanical connections (essential for proper electrical connection) at the contact points to prevent any dust from getting in between those contact points.
While RAM slots are designed to allow the insertion and removal of RAM sticks, they are NOT designed to support this action over and over, and over and over again. Nor are the contact pads on the RAM sticks themselves designed for that sort of wear and tear. The spring tension in the slots will weaken, and you can wear down (even cut grooves - not good) the contact pads on the sticks too.
Not to mention, every time you handle RAM sticks, you risk damaging the sticks through dropping or mishandling and even ESD (particularly when the sticks are out of the slots).
You have not told us anything about your hardware, but I personally don't see how this can be a marginal motherboard or RAM - other than the possible contact wear and weakening of the tension in the slots I mentioned above. Otherwise, it seems to me the system would not work for several months after cleaning.
I do, however, suspect your case. A decent case will have removable, washable air filters, and proper cooling that pulls a sufficient supply of cool air
through those filters. Even when I had two dogs and the kids were still living at home, running around and stirring up dust, dander and hair, I didn't need to clean the interior of any of my computers but once a year, if that. And even then, I never pulled the RAM. I just lugged the systems outside and blasted them out with my filtered air compressor. I certainly had to pull and wash the filters 3 or 4 times a year, but I didn't have to clean the interiors.
I am not against using a clean pencil erasure on the RAM sticks. I do this often as part of a
repair job - or when the RAM has been sitting on the shelf for awhile and the contact points have been exposed to air/oxygen and a bit of corrosion has formed. And for sure, electrical contact cleaner (and perhaps even a little scrub with an
acid brush in the slots can do wonders. But again, once clean, and the sticks are inserted, you should never have to do that again. Just an occasional blast of compressed air should be enough.
Assuming permanent damage (to include excessive contact wear and weak tension) has not been done, I suggest you look at a new case, one that has removable, washable air filters, and lots of large (120mm or larger) fan support. I like Fractal Design cases.