A couple years ago we bought a new gas grill. We made sure to buy one that came with a propane tank because the tank we already had could not be refilled because of the new law that makes it illegal to fill propane tanks that do not have an overfill protection device (OPD). We kept the old tank as a back-up, which was about half filled, in case we ran out of gas in the middle of cooking a meal.

When we refilled our main tank at Ace Hardware this summer, which cost us $22 with tax, I asked if they do anything with the old tanks that do not have OPD's installed. The guy said they charge $5 to recycle them so I figured I would just keep the old half-filled one around as a back-up.

Yesterday as I was walking into Wal-Mart I passed their Blue Rhino propane cylinder exchange station out front. Two things occurred to me:

1.Their price for a cylinder of propane was only $14.24, not $22.

2. Could I bring in my old cylinder and and walk away with an OPD-equipped cylinder filled with gas for $14.24?

I looked on their propane exchange web page and YES, they explicitly state that I can bring in my old non-OPD cylinder and exchange it for a new compliant cylinder! No extra charge for the upgrade.

I will definitely do that with my old cylinder, but I have always felt uneasy about doing that on a regular basis. I felt like I was giving them a good cylinder that I took care of and knew its history and getting a cylinder that could have been mishandled or damaged in someway. But I guess if the difference is $8 for a fill-up I might have to get comfortable with the exchange program.