What did you salt the solvent with to get your mesc salt?
You could redissolve in a bit of water (or whatever) and drink, yeah, but know that it will taste very bad. Another option is washing but keeping the solvent you wash it with and evapping it separately so that you dont lose any alkaloids (but then probably the evapped wash will be very sticky so youre back to square 1 about it)
As for BLAB, no problem leaving in vinegar for a week, the most that can happen is that it ferments a little bit (forming alcohol) but I dont think it would so quick. Just open up the container and maybe warm it up to evaporate the alcohol if it has fermented, otherwise just proceed as normal
By the way, please use the thread title to say what the content of the thread is, otherwise we have to click to know, and this makes it a self-centered thread, making it impossible to help others that might search the forum and thread titles for the same question as you have.