I think the scrap "secret" is just keep at it. cindy, your system sounds like it works for you and you are using the pieces you cut up...definitely works for you! When "creating" scraps, I often cut my leftover pieces into the largest "specific" size. That way it's already trimmed up and ready to go.
Julienm1...after a time of sorting I get into a brain fog and have to walk away...doing it piecemeal as you are is a great idea.