I think it is usually better to cut rather than pull the dead leaves from iris. Use good sharp scissors. Might be a good idea to carry a small bottle of rubbing alcohol and disinfect blades every few cuts. Steve in Baltimore

I pull only those dead leaves that come off with no resistance. At this time of year there are alot of dead leaves that do not come off easily. I leave them for protection, but many people do clip them back. I really cannot say which method is better, because both seem to work. I leave the iris leaves and tree leaves that have fallen around the iris, because I consider it the more 'natural' state. Since I live in a cold area, I do not get much winter rot. Those who live in the South are probably better off clearing around the winter iris as warmer weather encourages rot and mold organisms.
Laetitia