There's a whole sticky'd thread about it in voided warrenty. Basically, you make up a mixture of boiling water and RIT cloth dye, and throw in your plastic part. The longer you keep it in, the darker your part is. Diff. parts take the dye quicker than others. Anything urethane takes extreemly quickly, and delrin takes quick to (mine took ~12 minutes). Just read the thread, tells you everything you need to know
