A heat gun on low in 4-5 second increments and an iSeasmo. For tiny shards and residual adhesive I would use 99% alcohol, a plastic opening tool to scrape along the plastic mid-frame, and a microfiber cloth for final clean up. I would do this for the entire mid-frame and everywhere there may be adhesive left over from the old screen.
If you ever have a screen that really comes apart, you can tilt over the ipad and tap it out then use packing tape (for instance on the battery) to stick-n-lift very fine particles--then do the above. If you use an anti-static mat, etc, you can also use packing tape to stick-n-lift leftover glass.
Btw, trust me, one of those little shards gets in your finger, it will fester and become a painful nuisance. And i cannot stress enough, always wear safety goggles, no exceptions.