To decarb purged oil, you’ll need either an oven, a hot plate (with stirrer), or something similar & a pyrex/heatproof glass container.
Pre-heat oven or set hotplate to 260. Place purged oil into container. Place into oven. Stir often. Once tiny bubbles stop forming (this is an actual physical manifestation of the carbon molecule releasing) the oil is decarbed. Caution: the bubbles can really, really foam up! I mean REALLY, REALLY foam up! This is normal, so be prepared!
In my experience, using my oven, it takes a minimum of 30 mins but up to 90 mins, depending on amount of oil.