I have the exact same problem. While I haven't dislocated it putting a gallon of milk in the fridge, I used to do it regularly when I was rowing and we would do starting sequences.
The ones I do:
With weights:
Face down on a bench (1-5 lbs dumbells), arms straight along your body (just like when you are standing). Thumbs down, lift the heel of your hand towards the ceiling while keeping your arm straight. Think hitting someone with the heel of your hand as they stand behind you, only you are lying down. Do 30 reps.
Face down, arms straight out in front. Thumbs up. Raise your hands up while keeping your arms straight. Do 30 reps.
Face down, arms out to the side, thumbs up. Squeeze your scapula together to raise your arms, keeping them straight. Do 30.
Lying face up. Hold arms straight above your body. Use your pecs to squeeze your shoulders up off the ground. Hold 5 seconds. Release. Do 30.
With therabands:
Arm bent 90deg at the waist, upper arm and elbow held against the body (think old school fim noire pointing a little revolver at the bad guy). Holding upper arm close to body, and keeping forearm parrallel to the ground, rotate hand across your body. Do 30. (Theraband to the right when doing right shoulder)
Same as above, only rotate hand away from your body (theraband to the left when doing right shoulder, and vice versa).
Crossover pulls low-to-high: Holding arm straight, pull theraband from low (at hip level) to high (head level) across your body.
Crossover pulls high-to-low. Holding arm straight, pull theraband from high to low across your body.
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