Well as for cleaning the CBN wheels, it varies.... My first set, before the electroplated ones were available, was about 3/16 inch of a CBN matrix bonded to an aluminum hub. Woodcraft used to have a diamond one that was similar. This wheel did need to be cleaned because metal would load up on the surface. The place I got them from gave me some very hard aluminum oxide chunks to clean the wheel off with. I believe it is the same material as offered by a couple of suppliers for the modern electroplated wheels. Personally I won't bother with them, as the only thing they really do is put a lot of ALO dust into the air. The modern CBN wheels don't load up with metal on the surface, unless you grind softer metals on them. What does load up on the surface of the wheel is 'gunk' from the wood you turn. If you turn a lot of wet wood, this can be a bit of a problem. For me, most of the time I don't bother to clean it off. What I do, is regularly apply a bit of lapping fluid or light oil, to the bevel of the tool being sharpened, then sharpen as normal. This does a lot to help lift the gunk off of the surface. Note here, I don't apply the fluid directly to the wheel because it sprays all over the place. This is generally enough to keep the wheel clean enough to still cut well. In the event that you want the wheel to look better, according to Dave Schweitzer, the original owner of D Way, you take the wheel off the grinder, put it in a bucket, cover with water, add detergent, let soak for an hour or two, brush off with a stiff bristle brush, and put back on the grinder. I consider having a bit of 'color' on the wheel to being normal.
In the event that you do get some soft metal on the wheel, you can feel the tool start to bounce as you sharpen. So, to clean that off, again, apply some lapping fluid to the bevel of a heavy scraper, and sharpen the scraper. You may have to do it several times, depending on how badly your wheel is loaded up. I experimented once with an old wheel that was pretty much worn out. I left a very visible stripes of aluminum, copper, brass, and steel on the wheel, then went back to sharpening as normal. All visible traces gone in about a month. Do save an ALO wheel for softer metals though, it just makes things easier.
robo hippy