http://www.thepolishingshop.co.uk/acatalog/Polishing_Compounds.html MUCH better quality than the overly greasy tat machine fart, screwfix or the like peddle and cheaper too. As Scott and Langy said the machine needs enough grunt or all you do is smear compound around the job instead of generating the heat needed to get it working. FWIW i typically use 439T (which happens to be green) the most... it's got plenty of cut used with a sisal mop as long as you aren't starting with something properly manky and will also do reasonably good gloss . For finishing on a loose mop i tend to use p126 (pink) unless it's a softish flavour of sheet ally in which case i use 480blf (blue) which is greasier and makes it harder to burn the surface