Oh scurrilous and power hungry ye are, oh unwise and unqueethed one.
Whilst I am sure there are probably more than a few dubious ways of making money in this fair olde land; your 'idea' is not only quite ludicrous, but also potentially life threatening.
What, (if I may), if some old mare buys one your products and in fact, believes your charm and the powers that you bestow onto it, and decides to slay a mystical dragon with nothing but a blunt sword and an old battered shield. (no body armour)
She'd be believing that she has an amulet which will bring her the luck of the gods, she may well pick a dragon that is 30 or so levels above her natural fighting level. Any and in which case, without support, she would quite terribly die, a crispy death indeed.
The old Grandma would not only die a horrible death, but she would leave a family legacy behind; orphans, untold tales of love, and most importantly, a vast wealth of untold riches, which would be coveted by adventurers alike.
Maybe this is your secret plot. Maybe it is not. Maybe you want her to die so that you can claim her wealth and royalties.
Moderators, I would watch this one, he is marked with the mark of the unjust one.