3,421. Tevel Is Like Terumah

Hilchos Maaser 6:1

One may rub the outside of untithed figs and grapes as this causes no appreciable loss. Whatever non-kohanim may not eat when it comes to terumah – such as the seeds, etc. – may not be eaten from untithed produce, nor from tithes from which terumas maaser has not been taken, nor from second tithe or consecrated property that have not been redeemed. Whatever non-kohanim may eat when it comes to terumah may also be eaten from untithed produce, from tithes from which terumas maaser has not been taken, and from second tithe and consecrated property that have not been redeemed.

Hilchos Maaser 6:2

One is not permitted to burn (as fuel) ritually unclean untithed produce; this is the case during the week, and all the more so on Shabbos. This principle is derived from Numbers 18:8, which says “the watch of My terumah.” Just like ritually clean terumah may not be used until after it has been taken, one may not benefit from ritually unclean terumah until after it has been taken.