There are a lot of ways to beat a drug test:
* Fake urine, which can be heated to 98 degrees as indicated earlier.
* Real urine of someone else who is clean - you can inject this into your own bladder with a long hypodermic needle. Giving someone else you own clean urine has to be the ultimate codie act!
* They also sell very realistic fake penises for those that "watch" the urine sample being made. (I guess the plumbing would make this easier for females) and these can be used with either fake or substitute urine.
* Masking agents to fool the test - natural or otherwise.
* One of the most overlooked ways to beat a test is good old fashioned bribery. Not likely with law enforcement, but very doable elsewhere, especially in combination with one of the above methods.