I’m a fairly keen amateur photographer. Over the years, I have collected quite an assortment of vintage lenses, filters and other bits and bobs. I have also encountered quite a few sticky filters. However, I can honestly say that I have never destroyed a filter by attempting to remove it. Having the correct tool helps removing sticky screw thread lens filters. For a few quid you can buy dedicated lens filter spanners, as shown on the photo below. Mine cover a range from 37mm up to 82mm inclusive. All the filters in the photo can be removed using these spanners.
As an aside, a couple of other tips that some folks might find useful…
- Try moving the filter laterally – by pushing it gently but firmly from side to side before turning it. This can be particularly useful when the threads are painted and the paint itself is locking the thread. This often occurs with cheap step-up/down rings
- If all else has failed, then try applying gentle heat – from a hair dryer or better, from a temperature-controlled hot air source. I have a soldering station that will pump air at 100°C-450°C through a 8mm nozzle. Set it to its lowest temperature and hold the out[put nozzle at about 15 cm from the workpiece, so the air flow at the workpiece is around 50°C, and apply it all around the filter thread. Let it warm thoroughly, then try rotating it again. This is particularly useful where dissimilar metals are involved. Literally a few hundred nanometres expansion can separate the two threads and make the filter rotatable again. Obviously you need to be very careful not to overheat!