Just started a refurb on a mod 70(63)...A small amount of grass clippings led me to no surprise.All of this was pulled from shroud cover with screwdriver and hooked wire...Literally wanted to make newbies aware and remind the experienced that spring time is coming but mice have had all winter to build condos in the shroud...No. 1 is the fire hazard,no.2 is how such material restricts cooling of engine...Doesn't matter which engine,if there is an opening they will find it..,