Reusing old substrate - things to watch out for

I've done this a few times, but I'd take a few personal steps in order to make sure that everything is cleaned out of it, such as;

1. Wash it with water and vinegar in order to get any dirt, debris, or other items out of the substrate.
2. Try to use some type of sifting method to remove things that may look like the substrate, but might be rocks, stale/old items, or metals/other things that could have come in if the tank was stored somewhere like a garage or outside for any period of time.