Provided there is no clearcoat on the frame a gentle solvent based nail polish remover and a plastic scourer should remove the decal without damaging the paintwork.

Let the liquid soak in to the decal for a minute or so and then gently wipe away the now broken up decal. When you see the colour of the decal fade like a watercolour generally thats when its time to start wiping.

Then degreaser and a damp cloth should clean up any remaining residue.

I would personally avoid razor blades or plastic knifes etc due to the risk of digging to deep, respectfully.

I'm not sure if there is a clearcoat over the decals or not. On the left side about half the decal is gone. The right side decal is intact, but the clear areas are discolored and it just looks kind of crummy.

I would never touch paint of any sort with anything acetone-based. Goo-Gone, WD-40, and many of the other suggestions are MUCH safer, although they may take longer.

I have to confess, being somewhat lazy, i've taken the risk and used acetone based nail varnish remover a few times. It is right to point out that other methods are much safer as you say, absolutley.

I wonder would the non acetone version of that type of product be of any practical use though ?