Test your pills and molly before you take them..... especially if you don't know your source well.
Buy your shit from people who have standards as to what they put in people. This scene has some awesome individuals, its great to see people who aren't really in it for the money.
Know your source though, and try to find people who are not just in it for a buck.
And oh my god, any comedown you feel is pretty much adulterants, I took some like crystal mdma last night. I had a fantastic night and i danced my ass off.. Eyes were shaking around and i was faced off a little more than a tenth. That is how it should be, but it isn't even among respectable people.
Needless to say, i have never bought molly that i felt was cut with anything active, with one occasion there may have been some 2c-i in it but i was warned in advance about that, so that doesn't add shadyness to anyone.
As far as getting over a comedown instead of just pretty much avoiding one. Before going to sleep, bottle of water and a couple tylenol. Smoke a bowl, pack another, pass out. Wake up sometime later, smoke. Have some water, maybe smoke again. Take another nap. Get up and go eat something decently good for you, multivitamin wouldn't hurt.
Sleep, rest, try to get something decently good for you.... Im a fan of smoothies.