A precious chalice is fastened to an altar. There are controls to release the chalice from its fasteners. It takes DC 18 Disable Device or DEX check to disarm.
The bad news: no matter what, when the chalice is released, so is a boiling oil trap.
The good news: players get to choose how much damage they take from the boiling oil. Once dismantled, the chalice is worth as much in gold pieces as damage taken. If the amount is less than 100, then multiply the total by 10.
Chalice illustration Creative Commons cc0.