Ludwig Dude...
Ludwig was using plain old ceiling paint back in the day... inexpensive! ... and the finish was pretty much flat. It was also water based... not oil. Should you want to freshen up the interiors after trying a cleaning regimine with the "Spray-9", it will be pretty easy to do:
Because the white paint is already present on your drums... ( a plus! ) ... it will be a simple matter of getting yourself a quart of ceiling white, and putting on a fresh coat. Your existing paint will function as your primer, which makes it easy. I would paint it on using a foam brush, and there are a couple reasons for this:
The foam brush WILL NOT leave any brush marks/strokes, plus it puts on a nice, even, light coat of paint... and ... they are inexpensive, and no clean up is required. When you are done... toss 'em out!
I have in fact done many interiors with foam brushes using different paints/clears... they have all come out exceptional. Hard to tell that they weren't sprayed. So there you have it!
I think that you will be amazed with the "Spray-9" though... especially on white. The drums should look brand new... and the "Spray-9" will probably remove some of the black marks as well. Oh, I wanted to mention this:
I also us 3M Scotch Brite pads with the "Spray-9"... BUT! ... it has to be the WHITE Scotch Brite pad as this one is pretty much NON-ABRASIVE. There are FIVE grades of Scotch Brite pads... the white pads are the ones you will want. They don't scratch, but they have just enough of a texture to really clean well... especially when used in conjuction with the "Spray-9". Have a clean rag to wipe up the "goop" that the "Spray-9" and Scotch Brite pad leaves behind. Voila! Nice and clean looking interior!
Tommyp