Actuall yes you can, I began wearing dentures in September and I have filed mine down with emery board (the thin cardboard one's like you use on finger nails.)

Yes you can.  I've had my upper denture almost 20 years.  They gave me sore spots in a certain place when I first got them. So bad that I took them out every chance I got.  A couple different friends told me they 'do it all the time'.  It took me awhile before I tried it cuz I was afraid I'd ruin them.  Oh what a blessing is either an emory board or a little bit of fine sandpaper!  I still have to do it now and then.  But I sure don't mind at all.  It's free basically.  Try it, you'll see.

Yes you can.  I've had my upper denture almost 20 years.  They gave me sore spots in a certain place when I first got them. So bad that I took them out every chance I got.  A couple different friends told me they 'do it all the time'.  It took me awhile before I tried it cuz I was afraid I'd ruin them.  Oh what a blessing is either an emory board or a little bit of fine sandpaper!  I still have to do it now and then.  But I sure don't mind at all.  It's free basically.  Try it, you'll see.

I got dentures from Mexico too - and they were a horrible fit.  The dentist in town tried to deal with them but could not get them smooth enough to glue in and stay without hurting.  Disgusted I could either throw them out or work with them myself.  I tried the emory cloth, but the work I needed to do was too extensive.  I finally got my dremel tool out and put a sanding disk on it.  It took three or four grindings but I finally got them to fit really comfortably, but they were still a little loose.  With the jagged edges gone I had to find a good glueing method.  Tried Polident and did not like getting the paste out at the end of the day.  Tried Fixodent and it was dry and seem to suck the roof of my mouth - left it feeling tired after awhile.  Then I finally hit on a really good working solution.  I sprayed my dentures with a mist of water.  Alied the fixodent, and misted the powder again until it was in a puddle of water.  Stuck the dentures in and the extra water squeeshed out, leaving a really nice gel that held the dentures perfectly, and was easy to remove at the end of the day.  Just be careful with the sanding tho.  Do a little at a time until you get a good, painless fit and you will do great too!!!