seat belts

I also used Rit dye,black.As Tina stated,add salt to the mixture.What I did was boiled water,a lot of it,to fill a homer orange plastic Home depot bucket,then mix in the dye and salt.I believe I used two packs of dye (Rit states the results can be less than optimum with manmade fabric,therefore the boiling water/strong concentration of dye technique).I did some gentle aggitation,leaving them in for about an hour.You can use a L shaped stick to aggitate/pick up and down the belts.Afterwards,you will have to rinse them with cold water a few times,because they will run,maybe even using warm water.If you can do this in the summer sun,it helps with the setting process to let them dry in strong sunshine.Mine came out real nice,but if you had frays,rips etc. they still will be there,but they will be original!!!Ofcourse,clean your belts real good first.The bucket works good for that also.You don't have to worry about damaging your washing machine.You might also want to carefully cut the thread holding the date tags on each belt,so you can remove the tags so they won't get dyed.Good Luck.