depends on the age of the cue....IMO. I have used pliers with towels and left deep teeth marks that required a new bumper. I have also used the handles of pliers that were already cushioned and they popped right out. I have noticed that the ones that will leave marks tend to be the older cues, like the bumper material has hardened and is less flexible.
I do not recommend a flatblade screwdrive or anything like that to pry it out, as it will not only leave marks on the bumper, but will leave gouges, etc. on the buttcap which are not so easily removed. I would recommend contacting a local repair guy and seeing if they have the tool and would remove it for you. It may cost a couple bucks or a beer, but much cheaper than repair a buttcap and buying a new bumper.
Hope this helps.
Dave