Has anyone replaced the PEI sheet on their print bed? I tried using some of my sisters M3D tough ink and it failed and left some residue stuck/fused to the bed. Shoertly after that the pogo board failed and since I replaced that nothing's been sticking to the bed. I tried cleaning it with some acetone and it looks like that partially dissolved part of the PEI. I found this site and I was wondering if anyone's had any experience with it? http://catalog.cshyde.com/viewitems/3d-printing-materials/ultem-pei?