Making meth is pretty darned easy. The difference between methamphetamine and pseudoephedrine is a single 'OH' hydroxyl stripped from the molecule, then it's gotta be turned back into a hydrochloride or it won't be absorbed.
We'd get called because the new property owner would discover a evil looking pit in the yard with a neon yellow crusty crud in it. Might even smell bad. This isn't really a hazardous material--most likely it's all the cornstarch separated from the pseudofed pills, representing the biggest volume of waste (from a haz-been's perspective, everything is a poison, it comes down to dosage. Even the cleanest water is fatal if inhaled).
The other possible wastes depend on the method used to strip the hydroxyl. Sometimes lithium would be harvested from camera batteries, and used to pull the OH's away. If this is the case the lithium has already reacted and isn't much of a hazard (still worth calling a waste hauler to handle) Another method ('Nazi' method) used drain cleaner like 'Red Devil'---pure red phosphor. If there seems to be red/purple staining somewhere, again---get the professional cleaners out. (Note---anyone very familiar with this process---I know I've left out key steps and ingredients. Please don't fill in the blanks. I'm all for owner/building houses, but do not wish to in any way ecourage owner/builder pharmaceuticals)
The other stage of production, turning it into a hydrochloride, produces lots of toxic wastes. I've been to a house full of dead people because of inadequate ventilation. Nice thing about volatiles is they go away on their own. The HCL is generated from white gas, regular gas, even rat poison. And people put this crap in their bodies.....If you suspect a former meth operation on a bargain property have the spetic system carefully checked to make sure they weren't dumping runoff down the drain.
Evalutate from a distance---are there areas where plants will not grow? Are there dead birds all over? (If birds fly over your property and die in mid air that's a bad sign unless you're shooting a