Guys, as usual, Ive searched the board - but cant find the exact answer to my question. I am coming to you vets for help here. I just received some amps of Nile Sust. that are not pre-scored for easy opening. All of the sust I have had in the past, I could simply pop the top off. These suckers will not pop off. I read several posts that said to "file" the neck of the amp. I am NOT a tool guy - so what does "file" mean and how do you do it. I have never had to do this before, so I am really frustrated here. I am not a newbie, and am feeling really dumb here. Please shed some light for me and feel free to be very detailed! Thanks!