I used to use a credit card number when dealing with Brian via e-mail. For security I would leave off the last four digits and then give them to him in a different e-mail when he indicated he was ready. I don't how it will work that way now having to deal with Steve via snail mail.

1967 BSA Wasp
1967 BSA Hornet (West Coast Model)
1967 BSA Hornet (East Coast Model)
1968 BSA Firebird Scrambler
1968 BSA Spitfire Mark IV
1965 Cyclone Competition Build