What is sure is that you can sacrifice trash weapons in your inventory.
But weapons of the same family are the only ones that will give plenty of experience.
First, use trash weapons. Then buy the weapons of this family from Brunt and consecrate them to green then sacrifice.
I have not paid attention if there is a plasteel return. I don’t consider plasteel as a problem now (but I continue to loot everything, even on maelstrom).