Comet+ scotch brite pad for me, too.
The whites are sintered to closed pores. They have practically no wear. The grays are sintered to open pores which is a much more loosely bonded structure and will eventually wear.
Leonard Lee says, that ceramic stones can eventually glaze over and can be refurbished with a diamond hone. Sal Glesser however says that rubbing the whites with a diamond hone will grade the whites finer (he suggested that treatment for the whites for those, who wanted a finer grid, before the UF rods came out).
The whites are sintered to closed pores. They have practically no wear. The grays are sintered to open pores which is a much more loosely bonded structure and will eventually wear.
Leonard Lee says, that ceramic stones can eventually glaze over and can be refurbished with a diamond hone. Sal Glesser however says that rubbing the whites with a diamond hone will grade the whites finer (he suggested that treatment for the whites for those, who wanted a finer grid, before the UF rods came out).