AAAAAAAAAAAAAAAAAAAAAARRRRRRRRRRRRRRRRRRRRRRRRRGGGGGGGGGGGGGGGGGGGGGGHHHHHHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Moderators, PLEASE put up a page detailing this. GOD KNOWS how many times this question has been answered!!!!! READ OLD POSTS GUYS!!!!!
OK, first DO NOT use pencil erasers if you care for your carts or machines. Apart from shavings making things worse, it leaves a layer of rubber on the contacts i.e. they are still dirty.
I have always used and always will use contact cleaner. Those who bother to read this section on a regular basis will know I do! Its available from radio shack, mcm electronics, maplin, rs... go look! Aerosol can, NON-LUBRICATING type (NOT pot cleaner). Its basically isopropyl alcohol. Use it with cotton buds.
And guys, its NOT just for MVS. You don't need to open them. The contacts are those gold bits sticking out in the hole in the bottom. Aim the nozzle, squirt, and run the cotton bud along the contacts. No opening, works for AES.
And for all US residents... q-tips is a brand name. Its a bit of cotton wool on a stick. Doesn't matter about the brand!