For stamps on envelopes with fugitive colours, you can soak them separately from others, one at a time.
For self-adhesives, you can use a readily available product called Pure Citrus and spray it on the backs.
If you cut closely around a stamp you can put a few in that way, but I wouldn`t recommend it if you intend to sell them or exhibit them some day. But if you cut around them constantly, your stamp album might be twice as heavy as it needs to be one day! And do watch out that you don`t create any cut or short perfs!
