Here are some known tips to get the shaker to open easily. Give them a try, and let me know what worked for you.
How to Remove a Stuck Lid on a Cocktail Shaker?
There are several possible causes for this situation. A sticky residue on the inside of the cup or strainer, the contracting of the metal cup as it gets cold, or a mismatched strainer and cup combination can all cause this problem.
Possible solutions:
- Tap the shaker against the edge of the bar where the strainer and cup meet. This can jar the top loose.
- Another thing to try is placing the shaker in a bowl of ice water for five minutes, then dip the top in hot water. Sometimes the temperature difference between the top and bottom will set the strainer loose.
- Soak the shaker in hot water. This is the simplest and usually the quickest way to get the top off of the shaker. If the shaker was gummed up with sticky residue, the warm water would work to dissolve it. If the shaker was fused because the metal of the cup contracted around the strainer as it got cold, then the warm water would loosen it up.