Hi tchi6

When there are price rises for our prepaid products there is always a grace period where old satchels/envelopes will be allowed through without incurring underpaid mail charges.

If these satchels are a couple of years old as you have stated, that grace period will have passed because there have been a few price rises in the meantime.

If you were to send them now without adding extra postage you would likely receive an underpaid mail bill back for the difference in postage plus an administration fee.

If you know how much you paid for them originally you could put stamps on the satchel for the difference, or personally, I would just bin them as not worth the risk. It is your decision though.

Alice