I tried to remove sticky tags with heat, alcohol and acetone.
Step 1: Method 1: Heat
It did help in removing paper but the surface of the book still remained sticky.
Step 2: Method 2: Alcohol
Step 3: Method 3: Acetone - WINNER
Now I could move to the front cover and remove 2-for-1 tag. I simply rubbed it with cotton ball damped in enamel remover and it peeled instantly. Later I just pressed cotton ball over the sticker and it got damp and could be removed in one piece.
No residue left and no harm to color.