Keys are guaranteed to be secure -- I have no interest in your stuff, really, and I don't know who you are anyway. Chat soon!
I'm selling 'guaranteed secure*' bitcoin addresses too. Wanna trade wares?
*Fine print: Goods sold are not refundable and neither shall damages arising from the use of the product being sold be reimbursed.
On a more serious side, I think you'll do better selling/coaching the method used to obtain the keys and how to do it safely.