Hi there. I'm new to the forums and pretty new to Mooneys.   We bought our first plane this past April, a 1981 M20K, and have put about 25 hours on it so far. It just went down for annual in July as well as an avionics panel upgrade.   After we opened it up and took off some interior siding we found that a family of mice had moved in and proceeded to eat up much of the insulation and spread their business about the steel tubing in the cage and a bit into the left wing.   We figure they came up t