How do I remove dog kibble from the printer?

I left the top open with a sheet of paper ready to print in the morning. In the morning I printed the 8x10 photo then changed the guides for 13x19 paper. When I tried to print it sounded like a machine gun. There were many dog kibbles that had been hid by a mouse who has been steeling dog kibbles and hiding them; this time in the printer. I got most of them out so it doesn’t make noise, but it doesn’t feed evenly and jambs. I’m sure there is one more kibble that I can’t find. How do I remove the outer layer of the printer to get at the inside?