Another Washington Question

I bet you guys get tired of hearing questions about them
least this ones not about if this is a #544 (it's not) it's perf 12 no wmk

I don't really collect these I have some and look periodically
this has the appearance of something on the back? (probably transfer)
Could be something stuck to it (not the first time) I'm not very good at this
Not a fan of fugitive ink for soaking things before asking (made mistakes before)
Anyway looks like the back has offset and something else?(glue soaked in ink, maybe)
I'm guessing these are ok to soak but figured I'd ask beforehand
What is it?

it might have been used on a card or envelope that had a little square in the corner to remind you to put a stamp on it and some is still on the stamp or it could be transfer from an album page.

I was think along that line
Would that give it a raised above the paper appearance?
I'm picturing like rod mentioned to me in another post "peel off" (the thing that it was adhered to must have had fresh ink) fresh glue would soak it in if it reading right( good chance I'm not)
Not sure if this shows well :(

Soak the stamp in clean, cool, water; the hinge and other bits should float off.
Don

Thanks don
how long do I let it sit it's been in about 10 minutes so far

It can sit a while, you can gently try to persuade the hinge and bits off but be careful, wet paper is fragile.
Don

I'll probably come back with a thanks
But I hope I learned from last time!
Hinge is off but the rest remains so far...it almost looks like it was thinned

Apparently I didn't learn my lesson...thanks
For future are all of the W/F ok to soak with out fear of damaging
(Not a fan of fugitive inks, lost a nice Russian stamp to that lesson)

W/Fs do not have fugitive ink. You can soak them when necessary to remove hinges or other debris stuck to the stamp, but as stated above, take care handling the stamp(s) when wet.

Thanks, good to know!
Next time...I'll soak before asking (lesson learned)