The biggest problem with Soarin’ is the projection booth, like others have said it needs to be kept very clean. Any dust, mold, mildew, etc. will affect the show quality of the film, but the film isn’t the big problem itself, it is the “Field Flattener” , basically 2 pieces of glass with a vacuum system that pulls the film in and keeps it flat and steady and that vacuum system also pulls all kinds of dust and specks. The Field Flattener also has a wiper bar that can clean the lens, so most of the time it is the Field Flattener that needs cleaning not the film itself.
But unlike at most IMAX movie theaters the Field Flattener is cleaned between every show, Soarin’ was being cleaned once a day at night and now it is being cleaned twice a day. It could probably be cleaned more often, but there isn’t that many projectionists and even fewer IMAX trained projectionists.