Most interfacing is polyester - which could melt at high temperatures - so i would be a little concerned. Why not cut a piece of the fabric with interfacing, heat your oven to say 475 degrees....then put the piece fabric side out on an old pot holder with a piece of scrap fabric between them and take hold of the oven rack 20-30 seconds....see if it seems OK. Also....i have occasionally steamed ironed on interfacing - holding my iron above it and doing a bursts of steam - and sometimes it will mostly come off.