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Two filter wrenches will do the trick.
If you don't have the time to buy them, then you can also try using two rubber bands.
There's a technique to removing filters--never grasp the filter too firmly. If you squeeze the filter too hard, you momentarily distort the ring just enough that the filter threads will lock. In other words, the resistance increases the harder you grip. And never screw the filter on tightly--only turn it until it just begins to stop and catch.
To remove a filter, grasp the ring lightly and evenly around the entire circumference, and turn gently. Another common mistake is to turn in the wrong direction, inadvertently tightening the filter. To avoid this mistake, the rule is simple: if you point the face of the filter toward you that is supposed to accept incoming light, turning the ring counterclockwise loosens the filter, and turning clockwise tightens it.
In many cases where the filter(s) is/are undamaged and have not suffered any impact, stuck filters aren't really stuck. They only feel stuck because you're exerting too much force and distorting the ring in the attempt to unscrew them.