The 108 part #s are 6 1/2 x 14. I think the 126s are also. They will fit 107s and 123s.
I use orange cleaner concentrate diluted about 3-1 in a spray bottle and scotch brite cleaning pads. The surface on the back of the wheels is anodized or similar and very durable. They clean up real nice with a little elbow grease.