Hi,
We want that the local business are able to sell our vouchers.

The problem is that we have to print them in advance in some way that the codes are only visible to the final user.

So far I was unable to get those special "auto copy" envelops or "scratch card ink".

Any other ideas or places to get those elements?

Cheers
JD

Which country and city are you located at? I guess many places offer such things, but better would be to look locally.