I have found the best solution to be a little bit more spendy but makes a world of difference. I invested in an air compresser. First, knock all of the loose dirt into the cup. I then blow the bag out very thoroughly. If you have an extention on the hose, you can eliminate the dirt in the top of the bag when the metal fitting is taken off. I usually run the vacuum to help flush the system out too. I used to have the problem with the bag popping up on one of the corners. However, since I now use the air compressor, I just pull the bag out, blow the dirt out of the plastic ring and voulaa we are ready for another hard days work. Also works great with the portavac. This way I don’t have to move dirt twice.