For rugs I’ve always used plain warm water and a white towel with a rock over night. Then the same with the detergent you want to use also. Test all the colors and it doesn’t have to be large areas but you do want to make sure you saturate enough down to the fibers base. I do that if I’m concerned based on what the rug is. If I don’t get migration into the towel the next morning I clean. Sometimes I’ll just test with hot water first then the detergent and if I feel ok about it clean right away. When I do this I rub the towel along the face down to the base and also the backing. To be honest with you I know some of the most expensive rugs can be bleeders but if they do to me they’re pieces of crap. I’ve had some that bleed with plain old water and if they aren’t bad I just hit them with a dry compound and vacuum it out the next day. If they’re urine contaminated or really filthy and need a wet clean I just pass. I actually have dye block but I just don’t wanna deal with excessive bleeders although I know it can be done.