How can you remove a cat urine smell from a old dry clean only jacket?

Take it to the drycleaner and mention the pet stains when dropping it off.

It will most likely need to be washed to really get all the urine out, and most dry cleaners don't want to put urine in their solvent anyway. Washing will make the comforter smell much better, reducing your aggravation over paying for it to be cleaned and then still having an odor, and reduce the likelihood of your cat smelling the urine and continuing to urinate on the comforter in the future.

It would be advisable to take a large (Queen or King) comforter to a dry cleaners or a laundromat with extra large capacity machines for best results. Most home washer/dryers are not equipped to handle such heavy and large loads, and if there is not ample drying room in the dryer the comforter either won't dry, may damage the dryer, and have been known to catch on fire.

However, with washing a dry clean only comforter, you run the risk of shrinkage, color fade, the stuffing clumping, and depending on age and material, the fibers literally falling apart.

If the comforter's material is polyester and/or down, washing should be fine. Acetate, silk, or rayon run higher risks of the aforementioned risks.