This doesn’t really answer your question, but since I’m working with horribly complicated architects drawings (why do they do that?) every day here’s what I do.
I don’t get rid of anything. Depending on what you’re doing, that thing you just got rid of might have a significance later on.
I move all the architect’s layers into a new layer so that I can turn the architect’s drawing on and off at a click. It’s mostly off because as you say, the drawings are very complicated and that makes working on top of them difficult.
John