I know it's not strictly DIY, but I'm tasked with getting them apart !

Two bowls on the same diameter and are well wedged together slightly
at an angle. I wonder if they been taken out of the dishwasher hot by
one of the members of the family and have effectively 'shrunk'
together, but they certainly won't come apart.

Any ideas - I've tried hot water and then the deep freeze without
success - maybe significant oven heat ?

Thanks
Rob