One of the things I did was test the house for meth residue. Apparently this is unusual as neither the Realtor's representative nor the house inspector, both of whom were there at the time I tested, were familiar with the idea. I ruled out the option of having a test done because it requires state certification and the local company that used to do it just lost their certified employee. I did a little bit of research into test kits and picked a product called MethAlert, which is a quick screening test than you can run yourself in a few minutes. The main drawback of the test is that it only registers to 15 µg and Oregon will require homeowners to decontaminate if there is contamination present at a level of 5 µg. However, most properties I've heard of are far more contaminated than that (plus the instructions tell you how to find the most-likely-to-be-contaminated areas.) Also I felt I could carry out the test accurately and didn't feel so comfortable with some of the more accurate ones given that I'd be in a messy ad-hoc test area, not a lab. Plus it was inexpensive and simple enough to do multiple tests for confirmation.
Needless to say, my house tested clean or I wouldn't have bought it. However my friend sent me a link today to an article about a family a bit south of here who didn't test in advance and weren't so lucky - Oregon Meth House Owners Settle with Freddie Mac