Oil of Timelessness

A magic item found on UA 91.

Interaction with life-restoring magic

Oil of timelessness does not have any effect on the time limits for any life-restoring effects such as raise dead and reincarnation (see Death). This is because those time windows are meant to represent the time it takes for the soul or spirit to travel away from the prime material plane, not the decay of the body.1)

1)
DDG 10-11.