What information must deposit vouchers contain?

The voucher must contain a clear barcode for further disbursement of the single-use deposit for cash payment or as a credit note, and must be written in clear and simple German without any mistakes. Also to be indicated in particular are the number of single-use drinks containers inserted into and accepted by the vending machines, the amount of the single-use deposit and the place(s) at which the total amount shown on the single-use deposit voucher is disbursed.

All details can be found in the manual for reverse vending machines (RVM manual).