Quote Originally Posted by AgX View Post
The printing on a bulb can either be taken off with solvent or with an abrasive paste.
I've had to do this with a couple of actual enlarger bulbs, in fact. One of those safe scrubby sponges (that are fine on non-stick pans) worked pretty well.

And Freestyle has a few other enlarger bulbs if you have the 45MX - that one's different. I took a guess that you had a 23C.