It may be easier than you think. If you want to permanently remove the inner panes, and they are plastic instead of glass, simply heavily scribe a line across the inner window in a big "X". Punch the plastic in the moddle where the "X" crosses. The inner pane will break in 4 pieces. Remove the 4 pieces and clean the gunk out.
It's not a perfect world, so you may have to remove part of the inner trim to get at the edges of the inner pane, and either pull, pry, or scrape it off the frame.
Meddle not in the affairs of dragons, for you are crunchy, and taste good with ketchup.