As per the title; if you want to remove a radium from glass surface follow this desi jugad.
Put some kerosene on the radium part. Leave it for couple of minutes. Use a blade at around 45degrees on the surface. And scratch it. After that again wipe with kerosene cloth. Thats it. No scratches will be left behind on the glass surface.
If the sticker is on other surfaces than glass; then put some kerosene on the radium. Scratch with your nails slowly. It may be a slow process but it will work. The left out gum can be removed with cloth soaked in kerosene. Even a blade can be used but you need to be a pro in that. All the Professionals use the blades. They have judgements of the pressure to be applied. So for others strictly no blades on painted surface.
Last but not the least; I will not recommend any one to use PETROL on your car. Rather use KEROSENE or DIESEL; because petrol IMO is much stronger than the other two liquids. If not wiped on time might harm the paint. No worries in case of Diesel or Kerosene.
I got one such sticker removed from the rear glass of my car while getting it serviced. All he did was to sprinkle some soap water and clear off the sticker with a blade and voila. A task that seemed quite time consuming to me was a matter of seconds for them. Just for caution, clearly refuse to stick any kind of stickers on the car in future from workshops / accessories stores. The only sticker that I prefer keeping on my car is TAI’s sticker. Here’s an image of that sticker in question (Top Left).