For all the items I pulled out of magazines and even patterns I have bought, I have the plastic sleeves for ring binders and keep them in there. Every once in a while I will go thru them and if I have a "What was I thinking?" moment, I will pull an item out and throw it away. Since I only have 2 three inch binders they don't take up a lot of room. The only magazine I get now is The Block from MSQC and for now I like the magazine and keep the whole thing. If there is something special in one I put a sticky note on the outside of the magazine.
For electronic finds I save them to favorites and do the same thing. When there appears to be a lot, I go thru them and decide what should be deleted.