Fill a large stock pot about a quarter full with water (leaving plenty of room for the crab legs) and bring to a boil.
Add Old Bay seasoning, salt, vegetable oil, and beer.
Add crab legs and return to a boil. Steam crab legs for 5 minutes.
Carefully remove crab legs and set aside. Cover to keep warm.
Optional: Add frozen corn cobs in same pot and bring to a boil. Remove. Serve everything warm with lemon butter sauce.
For Lemon Butter Sauce
Melt butter and add garlic salt, lemon juice, and salt.
Notes
TIP—Crab leg cracker: If you bought your crab legs pre-scored, you can easily remove the meat from them by prying them open with your hands. Otherwise, you can crack them carefully by hand or use a crab leg cracker such as a lobster cracker, nutcracker, or even a meat tenderizer.Carefully crack the crab legs with your tool of choice to avoid breaking too much of the shell and getting shell pieces in your crab meat. Once you have the crab legs open, you can easily remove the meat with a fork.