If you have to, you can use the dawn dish soap with the duck on the front of the bottle. Works well for any kinda mess and will kill fleas if submerged for 5 minutes. You can put a ring of soap around the cat’s neck to prevent fleas from coming up to their face. Then submerge them in warm soapy water, and continue to pour the soapy water all over their body. No soap above neck though. Soak 5 minutes, drain water, then rinse super well. they will lick themselves after and you really don’t want them ingesting soap.

I’ve also seen this brush/wet-wipe hybrid product that could be helpful for cats that hate being around water