If you are posting cash (not really a good idea I know, but some people still do) do think before posting it just first or second class as the maximum compensation available (if the post should go missing) is �36. You may be better sending it by special post, though this will cost you quite a bit more (�4 or �5). You can even get special special post bags from the post office which are plastic and silver in colour so it's not obvious what is in the envelope.
Hi - I still post cash (notes) to my grandchildren for birthdays. But on the advice of my postmistress, I send the birthday card separately. Then send the cash in a plain white envelope, with the note/s inside a folded sheet of writing paper, and address the envelope to Mr. Whoever, (even though the recipient is a small boy), or Miss Whoever, so that it appears to be just a normal letter. I have been doing this now for several years, with no problems whatsoever.
By the way, yes, you can still buy carbon paper, it is used in some types of receipt books, invoice books, etc. I'm curious as to what the purpose was in wrapping cash in carbon paper before posting. I would be interested to know the answer.
you would not get compensation if posting cash by 1st/2nd class post because it is not recommended.
Special delivery would cost �4.60 - �5.05 depending on weight/what you send with it & that would cover you up to �500
The reason for the carbon paper is that some people think (wrongly) that it prevents the package contents from being identified on X-ray machines. Carbon paper does cut down the effectiveness of X-rays, but the contents can still be seen.