Frozen beer is a common result of trying to chill your cans or bottles in a hurry, and the delicate task of safely thawing it requires patience. Trying to thaw it quickly -- the flip side to your original mistake -- can result in cans erupting and bottles cracking from the pressure due to the rapid temperature change. Even when you're careful, the beer won't always recover with aplomb. If it comes out watery and flavorless, discard them and start fresh.
Place the beer in a covered container or zipper food storage bag. In the event there is any leakage, this will prevent a mess. Do not open the bottles or puncture cans.
Put the beer in the refrigerator or other cool location, such as a garage or basement. Avoid putting the beer in warm or sunny areas because it might cause it to thaw too quickly and blow the can or bottle.
Allow the beer to sit until it has reached has defrosted, often 12 to 24 hours depending on the temperature of the refrigerator or other location.
Beer that's only half-thawed can be a pleasant treat in its own right on a hot day. Alternatively you can add ice cream to the slushy beer for an adult take on the ice cream float, a treat that works especially well with stouts and dark ales.
If your thawed beer is watery and unsatisfying as a beverage, it can still be used to make beer bread.
Do not run glass beer bottles under hot water because the glass might expand too quickly and break.
Avoid shaking beer cans or bottles during the thawing process since this will only increase the pressure.