Well if you can`t find a CDrom or a USB port available my guess is that you will have to do it the hard way,
I think you will have to remove one of the panels of the tabletop and unhook the CPU,
then with the CPU box out you will be able to install a CDROM drive or a floppy drive and then you will be able to feed more games to it.
You could also unhook the Hard drive and plug it to another computer as a secondary hdd and from there copy more games.
By the way congratulations you got a great tabletop cabinet, all black it looks great! congrats, it looks very good.
Well Iīve used the Qtip moistened with water method with over 300 carts and they all work, some of them have been with me for like 20 years and they still work fine. But of course never insert a cart without allow it to dry for a few minutes, it should be completely dry before you plug it in.
If you have Iso alcohol at hand well of course it is better than plain water, but it wonīt hurt either to use the damp Qtip method.
Best choice would be to use Electrical Cleaning products, you might be able to find them at Radio Shack or Steren Electronic Stores.
Armor All is only good for plastic surfaces I do not recommend to apply it on the contacts as they may get all messy and greasy.
The Weiman kitchen cleaning product I think is overkill and the chemicals it contain may be way too strong and I donīt doubt you probably used it with success to bring back to life highly corroded contacts with it but still it sounds like an overkill.
I use Q tips and water too, I dip one end of the Qtip in water, wipe the excess and scrub the cart contacts until they look clean, the Qtip will look dark of all the dirt it removed. Now use the other end of the Qtip leave it dry and scrub again the same area and the contacts will look shiny. That should do it in most cases.
Also wait a couple of minutes before plugging in the cart you cleaned to allow it to dry.