I have been a stamp collector for many years but still have trouble identifying "secret marks" and watermarks which differentiate many of the early issues.
I read somewhere that having an example of, for example, a stamp with a secret mark, is very helpful. But if you can't identify those in the first place, how do you go about getting that sample for comparison?
Even when I use watermark detecting fluid, I still have trouble with US watermarks. And I worry about the chemical that is needed (I have some now, but don't like using it). Do others of you have these same issues? Do you have solutions? Do you where some kind of mask when working with watermark detecting fluid?
Experienced stamps need a home too. I'd rather have an example that is imperfect than no example. I collect for enjoyment, not investment. APS Member #223433 Postmark Collectors Club Member #6333 Meter Stamp Society Member #1409