Scott #418 Perf. 12 But No Watermark

Question and confession...I have a #418 that I am positive is perf. 12 but I cannot find a watermark. I find nothing that says there is a type like this. Now the confession...I used butane and rubbing alcohol because that has worked on another stamp. Not official watermark fluid. Thoughts?

You will still have a Scott 418. The single-line USPS watermark is spread out and staggered such that very often a stamp will have only a very small portion of a letter or two .... giving the appearance of having no watermark.

Single line watermarks can be difficult to find. Can't say I've ever used butane or rubbing alcohol. Lighter fluid works great and that's all I use. Can't confirm or deny if those damage stamps. All that aside if your stamp measures at perf 12 then it can only be a Scott 418 so you avoid having to look for those pesky watermarks :) You say you "are positive" it is perf 12, did you measure it with a perforation gauge?

Thank you for the information about single line watermarks being so stretched out. I have three different perf gagesso if I question one, I try another. The butane dries quite quickly but I let the stamp air dry about 30 minutes before putting back in glasine.Thanks again.

I believe Butane is essentially lighter fluid. I would suspect that as a watermark detector butane would provide the same level of detection. My bottle of Ronsonol states" light petroleum distillate". I am wondering if other such product would be equally effective. Think gas.
Just a thought.
Cheers mark