i trained with N.S.I acrylics then gel. i was told the seal would be broken if you filed the nails. i also trained with Calgel, been on extra day too.the first time i went i was told that you were able to file the nails ( exact words were teach your clients how to file their nails so when they came back for their infills, it would make my job easier). i have did this with my own nails, which were colour and were fine, but tell clients that a little light filing only if necessary should be ok. but i am not too confident in this because common sensse tells me if you have to wrap the product round nail to seal then the seal would be broken if filed. was i tiold wrong.