Great. One more thing to have to watch out for…
If you use a propane bbq grill or anything that runs on propane, please read the following warning. Follow the link at the end to see what to look for.
Meth cooks are getting the propane tanks from the exchanges at Wal-Mart, Kroger, Lowes, etc. and emptying them of the propane. Then they are filling them with anhydrous ammonia (which they now have a recipe for by the way). After they are finished with the cylinders, they return them to the store. They are then refilled with propane and sent back for you and me to buy. Anhydrous ammonia is very corrosive and weakens the structure of the tank. It can be very dangerous when mixed with propane and hooked up to our grills, etc.
According to the National Propane Gas Association, you should inspect the propane tank for any blue or greenish residue around the valve areas. If it is present, refuse to purchase that one.
Check the following website for more details and pictures.