One of my cats is very prone to chin acne. It never got beyond a mild case of black specks around her chin and along the jaws near the lips but that may be because I keep on top of it. After speaking to our vet, I soak/wipe the area with witch hazel on a paper towel at least once a day - more if it starts to act up.
When she developed a cyst (fluid filled swelling) on her chin, I treated it several times a day with a towel and very warm water. The cyst finally went away (either naturally or due to my treatments or both) but I noticed her acne was under control without the witch hazel. Since then, I have been using nothing more than warm water and a towel once or twice a day and the acne is under complete control. I'm thinking the warm water and rubbing keeps the oils off and the pores clean. If cats have pores, that is. Not only is plain water better than any chemical, but she enjoys the warm chin rub very much.
Start with very warm water in a small bowl and dip the end of a small towel. Wring it out a little and wet the affected areas. Start with the towel fairly wet since it is difficult to saturate the fur down to the skin. Rub all around and back and forth, not just with the fur. Keep dipping and wringing the towel so it remains warm and on the very damp side. Continue for at least five minutes. Repeat as many times a day as necessary. I started with four or five and now do just twice or once to keep her completely acne free.
By the way - I switched from plastic to ceramic bowls long ago, but this didn't seem to make any difference in her case.