462 has a unique non-skid with deep pockets that trap dirt. Short of using a power washer, the only way I can get it clean is to use a stainless steel
wire brush either manually or on a drill motor
. No chemical I have tried will touch it unless I use the wire brush. I keep hoping that if I use the wire brush enough, maybe some of the non-skid will wear off and open up the pockets - so far that hasn't happened.
A high power washer will do the trick quickly, but also it removes get coat in a few small spots. Definitely not a good compromise.