Used it in the washing machine, as recommended on the iDye web-site and it did not remove the dye - which was what I had dyed into the fabric a year ago - but I guess that might only prove that the quality of the dye I used year (also iDye) was really great! But I gave this a score of 4 as I have used this product before and it completely removed all of the dye that time - I seem to remember I used it on the stove top that time.