Removing the PEI adhesive residue

I just removed the PEI sheet but now have some residue stuck on the glass. Rubbing alcohol and glue remover seem to temporarily soften it, but nothing is dissolving it. How do I get rid of it without scratching the glass?

You can use isopropyl alcohol and a razor blade to help remove the adhesive. We have a guide here that goes over replacing a PEI sheet:

I used WD-40 and a razor blade, the oil cleaned up with alcohol after it was all scraped off.