Preheat barbecue grill (spray grill with vegetable-oil cooking spray). Drink (or pour out) 1/4 of the beer from the can.
In a small saucepan over low heat, melt butter or heat olive oil. Mix in garlic salt, paprika, cayenne pepper, herbs, salt, and pepper; set aside. NOTE: You can substitute any favorite chicken rub.
Cut off all the fat from the body and neck openings as you want the cavity free and clear; remove the giblets and discard. Rub the inside and outside of the chicken with butter/seasoning mixture (this seals the chicken and also ensures that the skin will be brown and crispy when done).
Slide the top of the beer can deep inside the chicken cavity (the bottom end). Lightly oil the exterior of the can with salad oil. If the opening is especially wide, a carrot or slice of potato can be slid in beside the can to seal off the cavity. Push until the can is almost fully inside the bird. The bottom of the can and the two legs bent slightly downward form a tripod which keeps the chicken upright on the grill.
Cover barbecue with lid, open any vents, and cook over low to medium heat for approximately 2 to 3 hours (depending on your heat source) or until a meat thermometer registers an internal temperature of 165 degrees F. (juices will run clear when cut with the tip of a knife). Check the chicken every 20 minutes or so and brush on more of the butter/seasoning mixture or olive oil as needed. If the chicken is browning too fast, cover the chicken with aluminum foil.
When the chicken is done, remove from the grill and let the chicken cool for 15 minutes before cutting and serving (meat temperature will rise 5 to 10 degrees after it is removed from the oven). NOTE: When removing the chicken from the grill, be especially careful as the aluminum can (and the liquid in it) will be very hot and you could burn yourself.
One chicken makes approximately 4 generous servings.
* Fruit juice, soda (not diet) or wine can be used in place of beer, but beer is the tastiest option (the beer vaporizes and soaks into the meat making it very moist and very tasty).
Beer Butt Chicken - Beer Can Chicken - Drunken Chicken Recipe: https://whatscookingamerica.net/poultry/beerbuttchicken.htm