1993 Cadillac DeVille Owner's Manual - Page 278

Or you can use the release lever located on the left side in the trunk. Pull the lever toward the rearof your vehicle to release the fuel door. To take off the cap, turn it slowly to theleft (counterclockwise). While refueling, hang the capinside the fuel door. A CAUTION: If you get gasoline on you and then something ignites it, you could be badly burned. Gasoline can spray outon you if you open the fuel filler cap too quickly. This spray can happen if your tank isnearly full, and is more likely in hot weather. Open the fuel filler capslowly and wait for any "hiss" noise to stop. Then unscrew the cap all the way. When you put the cap back on, turn it to the right until you hear a clicking noise.