Not knowing what paint has mold and how old Tilex will react, I do not know.

Try a test area, use another cleaner?

Eliminate moisture, let mold die?

Why do you have mold on a bathroom painted ceiling?

The mold damaged the wall already. All you can do now is kill it and replace the materials affected by it. . Aerate the room to dry it out. remove the paint. Make sure you use Proper Protective Equipment as not to inhale spores. remove old sheet rock and install new to make sure no further mold will still linger and invest in a bath fan to remove moisture. If its the ceiling on the shower area, I would tile that area as to make it easier for you to properly clean without having to worry about damaging paint in the future. Do it soon bc mold is a hazard for the health.

https://www.handymansgarage.com/best-mold-killer/

^^ Oh, that's way too much to take on right now. Moved into a house where the master bath has...issues.

So, for now all I want to do is kill the surface mold without ruining the paint -- it's a small area between the shower stall and the bath, and I do have touch-up paint if worse comes to worst.

Have you tried a bleach solution? Maybe mixed with a bit of Dawn detergent?

^^ No, haven't tried bleach yet, that's an idea.

Bleach will not kill mold on porous surfaces like drywall. And cleaning off the mold isn't going to address the problem of why it's there in the first place. You need to look at the cause to find the soution.

Please do not use bleach. It's not an approved mold killer.

Use Concorbium or an equivalent.

I think Mongo meant Concrobium.

I can't speak for the validity of this site but take look; it says that vinegar is better than bleach for mold.

Vinegar over bleach

" Bleach and vinegar can both kill mold, but vinegar is much more effective for removing mold from porous materials. This is because bleach only kills mold spores on the surface of affected materials. Vinegar will penetrate porous materials and kill the mold at the roots. If you use bleach to remove mold growth, there is a good chance that the mold will return. "

I had the same problem. I scrubbed ceiling with chlorine bleach and repainted with Kilz paint. Looked great.

DH sprayed with Tilex -- killed the surface mold and didn't take off the paint. So problem solved for now.

I thought the painter used the Kilz stuff to prime, but I'm not actually sure how he treated the mold that was there before (if he used some sort of mold killer first them primed, or just primed w/the Kilz right over it). Good to know about vinegar - that's another option if it happens again.