ive been doing this for a long time. I will say now do NOT use brasso, or weimans countertop cleaner unless you have to. For very filthy/dmgd carts ONLY. Just rubbing alcohol doesn't cut it either. After a lot of trial and error this is the best method i've found. I"ll skip how to clean the cart and stuff, thats pretty self explanatory. Only thing i will add is mr clean magic erasers work great for getting rid of sharpie and stuff like that
Heres the best way ive found to clean pins on the board. It uses a lot of elbow grease but works best and doesn't dmg the cart
1) Get a really good quality mars plastic eraser. Staedtler makes good ones
http://www.staedtler.com/en/products/pencils-accessories/erasers/mars-plastic-526-50-premium-quality-eraser/
2)take the board and lay it out on a mouse pad. The older thick style ones. f you lay it on a table bare it will scratch the shit outa it
3)Rub the shit outa the pins. Really get in there. Do it horizontally all the way across for a while, vertically, then go pin by pin. Get both sides. Depeding how ditry the contacts are this may take a while
4)Blast it with canned air to get all the remaining rubber bits off
5) Go over the pins slowly and carefully with a q-tip soaked in rubbing alcohol. 70 or 90% works. I prefer 90% because it evaporates quicker.
6)when done go over the pins with a damp soft cloth.. microfiber preferably, with some alcohol on it to get any residue or lint off.
7) one last canned air blast
done. If the pins are corroded or really messed up then as a last resort you can use some kinda cleaning solution on it. I find Weimans cook top cleaner works better than Brasso and doesn't seem to peel as much off from the contacts
This method takes a while but is the safest and gets stuff very clean. You just cant do too many at once because your elbow will start to hurt if your really cleaning them properly with the eraser. Once youve done this once, and cleaned out your console your set. Ive never had to re-do my carts/system after the extensive initial clean. It takes a while but works great