Note: Kriol is a penetrating fluid. Tri-Flo is a lubricant. Plain old Sewing machine oil really is your best bet for cleaning.
I agree, if you use Kriol (or the equiv), you should clean it up after the part is released an dif it is a moving part, use Tri-flo or oil as your lubricant.
I am SO not sure on the particulars of the newer machines, but it is my understanding that the toothed belts operate on the same pulley and wheel as the smooth belts