Opioids Heroin Purification Procedure

https://www.heroinhelper.com/user/admin/purifying_heroin_again.shtmlhttps://erowid.org/chemicals/heroin/heroin_info5.shtml I'm looking at using one of these two procedures to clean up some dope with the help of my friend. I'm no chemist but he's an undergrad student who's in organic chemistry classes. He's not super advanced, but it looks like simple stuff, and he knows lab procedure. I plan on reagent testing the final product. Is there any easy way to dangerously mess these procedures up? Are they likely to leave contaminants that are particularly dangerous?
It (to my untrained eye) looks like this procedure is a series of solvent washes which don't really change the heroin into anything but just remove possible cuts--then a procedure which turns it into the salt form. Either way, I'm trying to reassure myself that if a step is missed it won't be catastrophic. And that the solvents are the only toxic thing there, so if they're evaporated, it's totally fine.

I'm going this much before reading it myself, for salting it you need to know the pure base weight as to salt it properly to the point it doesn't end up leaving excess salt . I'm no expert so take my words with a grain of salt.

what's the danger of making excess salt?