With our really delicate, special occassion collars, such as the "beaded white wedding" design, I take a soft cloth and dab at the dirty spots. She doesn't wear hers often, so it doesn't smell. Her cherry collar and purple asiatic design get dirty quite easily, so I put them in a pillow case and wash them in the washing machine at the VERY gentlest possible. Then, I hang dry them. We sighthound people take collars very seriously *nods ferociously* I don't care about her nylon collar so I just toss it in the washing machine. I usually put it in a pillow case just for safe measure.