I used the filter put on ventilator cover (like sticker), but it wasn't peeled off completely. It was also tainted by dust so looks dirty. The ventilator cover is made by plastic. How can I remove it with less damage?
Certainly you can use sharp chemicals like alcohol, but especially on plastic I would not recommend to start with that. First I would try water and soap. Then non-alcoholic glass cleaner. Then you can buy a special fluid, made exactly for your case. You have to google for that, but it´s not so special. Big stores do have this label residue cleaner for about $10. It this still doesn´t work, you can try with alcohol (more or less mixed with water). Some label-glue can be removed with lots of work (rubbing with paper). Sometimes the label-glue changes the color of the plastic underneath, with no chance to undo this.
Rubbing alcohol that is 70 percent isopropanol alcohol dissolves the adhesive on stickers. Moisten a cloth with it. Use a plastic dish scrubbing pad to help break up the adhesive residue. Repeat as often as needed. I understand that it is much safer because isn't 100 percent pure alcohol. I can be purchased at a pharmacy.
Personally I wouldn't recommend ether, white spirit, or lighter fluid. They may be effective but the vapors can be easily ignited by static discharge. If you inhale ether it will render you unconcious. The others are potientially toxic if inhaled or absorbed on the skin.