Cleaning

first check your nuts.. and bands and bolts. make sure the bands are in the right place, the bolts are bent and nuts are tight.
next remove innards and vacuum inside clean..
re assemble add lump almost to the top of fire box light your egg replace the grid and stabilize 550 to 650 and let it burn for several hours.. this way all will be clean, no worries about mold or rodent residue spider stuff etc.
if this is too much trouble click the pic for additional idea

If that doesn't clean the grate, and you have a self cleaning oven, usee that.