Wrap a couple of elastic bands around the filter to give some grip. (your postman will no doubt leave some for you - just walk around with your eyes on the pavement).
Get an old leather belt & remove the buckle's tongue.
Make a loop in the belt by passing the end through the buckle & place over filter. A couple of extra turns on the filter might be helpful.
Pull to tighten and to apply torque in order to ,hopefully, undo filter.
If this doesn't apply enough torque on its own, assist it with your other hand wrapped around the belt.
This method has the advantage of not damaging the filter - unless the threads shear off of course.
p.s. Make sure you're turning it the right way. It's easy to get disoriented if you have to work from underneath.
Clean your wounds and apply first aid.