You don't. If you've lost the gum due to an accident, you can use the stamp with a bit of glue on an envelope. If you are trying to make it back into a 'mint' stamp, as if it was just made, it is fraud and can even be considered a criminal act.
Re-using stamps, known as "washing" that have come off delivered mail is also a criminal act.
A postage stamp: millimetres.
It is said that the stamp has been "cancelled".
A scale that will calculate the postage needed based on weight.
1
A postage stamp
It's unclear what you mean by seal. If you want to keep old postage stamps, you should buy a proper book to store them in, use hinges (some like them, some don't) or sleeves to protect them. You can't regum the stamp if that is what you mean. Once the gum (glue on the back) is gone, it's gone. You are not allowed to regum it.
What was the cost of a postage stamp in 2001
postage stamp
the postage stamp had cost $00.32 in the year 1993
The current cost of a US postage stamp is 44 cents
how much did a postage stamp cost in 2016
no lauren mitchell has not yet appeared on a postage stamp
Bill Gates should be on an postage stamp.
A first class postage stamp is $0.50 or 50 cents.
The current value for a standard postage stamp is 46 cents.
Right now, a postage stamp is 44 cents.
Austria is not a "postage stamp country". See Related Question, below.