They do work reasonably well, Eric, and I've kept one around for a long time for my sanders. They don't, however, clear truly gunked up material that can often be dislodged with SimpleGreen, etc., as some folks have note. I've come to realize very quickly that we can be our own worst enemies by taking more of a bite than we probably should as I noted in my previous response and that can contribute to some really hard to remove debris in the abrasive...it's pretty much "baked on" from heat that comes from excessive friction.