Those particular stamps can be washed
There are two kinds of self adhesive stamps:
- one with normal paper, to which the adhesive is applied
- the second- the paper itself is self adhesive
the first can be washed easily, the second can't- you need some chemicals to wash them= time consuming and not always successful.
New Zaland, Germany and French commemortives, Austrian
stamps- can easily wash.
put them in hot water, and after a while try to seperate gently
the stamps from the paper. make sure that all the glue comes off- pay attention to the edges-
USA, Italian and french definitive stamps- and UK self adhesive- do not attempt to remove- as the stamps would not be seperated from the paper.
Hope it helps