Rear tint removal is 50/50 punya la bro.
If it already too old, it might jus stick onto the heating element. Even I went to 3M authorized shop also the sifu will say terus might damage the heating element. All he say is try his best. I did mine in seksyen 16 shah alam.
Successfully remove rear tint without damaging the heating element. If you want his contact PM me.