I recently put new guts in our toilet at home. In the package of rubber washers and things was this thing (pictured). No Idea what it is but is rubber,ad just the right size to slip over the atty and completely seal the catch cup on a grand. I always put my grand in my pocket and it never ceased to get crud in the catch cup. with very little modding, I got this, it looks like it belongs on herbie (my grand) and it also keeps juice in the cup as well as dust out of it 
A red dirt REOnaut!!

A red dirt REOnaut!!