Put super cold ice water in the inner stuck shaker and let that sit for a few minutes. Then put the stuck together shakers in a pitcher of very hot water. Take the shakers out and they should come apart easy.

Hot water makes outer shaker expand and ice water makes the inner contract.

pop them in hobart for a minute and then try to detach them straight out, the hot water helps separate

Tap the top against a counter. Not hard or anything, but it should at least be somewhat easier to remove.