this is a good topic---one that doesn't get brought up very often. i clean my slide soles( #8 & #7 almost always ) with a wire brush after every time i bowl. this gets rid of a lot of the "gunk" that builds up. i usually use the #5 smooth rubber heel and always lightly sand off the residue from the approach. these two things really make for a more consistent slide...time after time. you might want to start using a shoe cover when you leave the setee area---it's really helped me.