I'm hoping some of you lovely and experienced folk can help me out with a bit of advice.

I used to polish everything by hand but just cant do it due to increase in orders. I bought a flex shaft (a while ago but havent used it properly), most of my work is very flat and when i tried the radial discs I just didnt get on with them as they were leaving grooves soooo ive bought some felt heads, cotton heads, tripoli and rouge and am getting on with these quite well BUT even though I'm cleaning the piece after using wet and dry etc the head when finishing polishing after tripoli and rouge (im obv using different heads for each one) is very black. Is this right? Do I need to prepare the heads in some way? Any advice would be great. Thank you ever so much