They can sell them if not in accordance with their mission by paying taxes on the sale as well (UBIT). There are very few restrictions on what a nonprofit can and can’t do.
in the USA ? that is absolutely not true.. could an actual experienced attorney please look into this ... I think you people are confused about "selling t-shirts" versus disposal of actual assets.
https://www.councilofnonprofits.org/tools-resources/unrelate...