This might be the wrong place to ask,but I need help. I had a Zagg protector on my Oregon 450 for about 3 years and tried to take it off yesterday. Half came off as it is supposed to, the other half left a residue of hard, dried glue. I've tried citrus based cleaner (recommended by Zagg), alcohol, WD40, Boeshield all to no avail. I'm chicken to use anything stronger for fear of damaging the screen. Any ideas?