Visconti Homo Sapiens Magma Ink Stains

Y’all:

I’m getting an ink stain on my thumb pad. I’m positive it’s from the trim ring closest to the nib.

1. Is it possible that the pen is leaking ink from there?

2. Is it possible it’s merely ink caught between the trim ring and body that I just need to clean more thoroughly? (I think this is more likely, and I used to have a very similar problem with the trim ring on my Pelikan M1000.)

Assuming it’s the second alternative, how do you all clean inky trim rings?