haven't made it myself but you should still be able to purchase it in adulterated (impure) preparations. here "curing salt" is really easy to get ahold of. have not personally tested this, but NaCl (table salt) and SN have different solubilities in water, with SN being more soluble at all temps. you could, in theory, dissolve curing salt in water and keep adding it until nothing dissolves. the solution is already more SN than the powder, but what precipitates first as it cools should also be primarily SN not NaCl because SN loses solubility as it cools, but table salt doesn't. you should be able to repeat this process to get it more pure. i found this looking for how to purify the curing salts online actually. i want to test it soon... i think 70-80% pure should be achievable? not sure. im going to order curing salt and test strips soonish, it's relatively easy of a process and i'll post about it if i do end up doing it
