Hi Roger. Not a dumb question. Slick-Lube is popular. You can get it here:

http://www.faimodelsupply.com/FAI3.htm

Sig sells lube, too. But they want $6.49 for a 4oz bottle.

Or, you can add glycerin to some dish soap and make your own "green soap."

BTW, Tan Super Sport is currently the best rubber around since FAI Tan II disapeared:

http://www.faimodelsupply.com/fai2.htm