What Yuitsu said. I had mold in my sparkle ponies, and rust, and I took pipe cleaners to them. I also used bamboo skewers with paper towel or a small thin cloth wrapped around the end and used that to get into all the corners. It worked well, but you'll be at it a long time, just to warn you. I also used boiling water to help loosen it all so a very small 'scratch/scrub' was needed to remove it. Good luck!