i guess excellent documentation also helps.

just put together a sheet with hatch date, genetics information, data on the parents, the first feedings, and a nice picture. and of course with your name, adress, logo, contact information, and signature. just print it in a copy shop if you dont have a good color printer.

that will forever remind the customer of you, and if the snake gets rehomed, it will most likely move with the snake. and store the digital version forever, with backups, for future reference. when someone calls you with a question about a snake and you go "wait, what ID number came with your BP? im pulling the data sheet for your BP from my database, got it, now lets see...", that looks really professional.

for dogs and horses they sometimes have real certificates with linages going back many generations and the animals are registered with online databases and stuff.