that fine cut stuff is just lower strength rubbing compound. the black u r getting is the oxidized paint. make sure you wax after using that. the heavy cut cleaners remove wax, oxidized paint, pretty much anything

1998.5 Ford Countour SE Sport V6 5-spd. Black/Gray with SVT 16inch wheels. approximately 89,000 miles 2004 Toyota RAV4 L Auto Silver/Grey Leather 4,000 miles