Soaking Stained Revenues

I bought a very inexpensive special tax stamp lot recently on ebay with the intent of experimenting with soaking them to try to remove the stains. A fellow collector had suggested to me that it was possible so I wanted to try it out on something I didn't mind destroying should that happen. This is the stamp I selected:



As can be seen from the scan, this stamp is heavily stained with what is most likely smoke. I first soaked it overnight in warm water and some gentle dish soap I use to wash my daughter's bottles. The result wasn't what I had hoped for:



While it did lighten a bit, I was hoping for more. It was suggested I try for longer with a stronger dish soap so I did. The result of the last soaking was better:



As one can see from the last image, the stamp cleaned up tremendously. The only issue is that the red partially washed out and now appears to be orange. I am hoping to try the next one from the lot soon only soak a bit less time to see if I can get most of the staining out without also fading the red.

Personally, I like the first soak, retains the overall condition.
The second soak looks to me like damaged.

Unless your scanner/image editing software is playing tricks, not only did this soap lighten the paper, it also turned the reds into orange. High bleach content?

It definitely turned the reds into orange. I mentioned that in the original post. I used Dawn Ultra Platinum which does contain sodium hydroxide (lye) but no bleach.

My first thought would have been to try hydrogen peroxide, not dish soap.

I never try to remove stains from special tax stamps. They were on display for an entire year, in this case in a store, a bar or a club. In any case it was some place with a lot of smoking and possibly a lot of drinking and dancing and other activities. I know of no way to safely remove those kinds of stains.

peroxide, stamp smarter-good write up with pictures-no dish soap as you found out-

I got the lot of 4 of these for $7.50 specifically to do things to them like soak them in heavy dish soap. The Retail Dealer in Ferment Malt Liquor is a very common Special Tax Stamp and really nice copies for the years I am experimenting on are readily had for reasonable prices, thus the experiments. Given the quality of the lot, I would not have considered purchasing it for my collection otherwise. I plan on trying hydrogen peroxide on the next one just to see what happens. The question I am trying to answer is am I able to rehabilitate some common special tax stamps, like liquor and tobacco stamps, without damaging them. I wouldn't actually try it on anything of higher value. For instance, I would love to remove the stains from either of these but wouldn't ever actually attempt it.

Both are scarce, but the In Lieu Of in particular is quite scarce.