I found 2 claybars that I used in the past. They have been sitting for awhile in a jar in the garage. They were kind of stuck on the inside so I pulled them out. They have been through winter also. One of them is claybar magic because I still have some lube left in the spray bottle and the bar is blue. I see some contaminants from use. Is there a way to clean a claybar for reuse? I dont get how you could keep using it, I know you keep folding it over and over when you want a new side. Do you think these are still good to use? Also whats the difference between medium grade and fine grade clay? What is claybar magic? I thought that worked good.