I've found that the "door hinge trick" will usually open almost all hotel toiletry products. I've noticed that people tend not to use that one much anymore, but it still works, just like my Mum taught me forty-odd years ago.

For anyone not familiar with it, open the bathroom door, hold the door handle in one hand and the bottle in the other. Hold the bottle at an angle so that the cap is sticking into the hinge opening. Slowly shut the door until the cap is firmly caught in between the door and the frame, then hold the door in that position and turn the bottle. Most of the time you'll be able to open it, seal or no seal.