I have wanted to do something similar to efficiently dispose of my child's toys. Step 1: I put a red sticker on any toy I don't think has been played with in a while. Step 2: three weeks later, if the sticker is still there then I take the toy and put it in a holding pen. Step 3: if the child has not noticed it was missing three weeks later, the toy can be recycled/donated.

We haven't done this yet, but it's on our list of things to try.

Have you tried this with your own stuff? Books on your bookshelves you haven't opened in 10-15-20-30 years?

I do get rid of my own things from time to time, but I also get new things much less frequently than she does.

I did something extremely similar with my not-quite-hoarder wife. She had an uncanny ability to ask about a thing the day before it was to make its way out our door. And my “holding pen” was 3 months.