Area 419 Powder funnel thumbs up or could it work better?

[imaguy3]

This hornady one is pretty nice for sure. The bottom weighted aspect of it allows it to balance easily on brass without being tippy. Additionally it releases from the case cleanly, my plastic one has stuck before.

In looking closely at my plastic one though I noticed something interesting.. I had building occuring on the inside shoulder where it funnels down to the hole, I scraped it off and it sure looks like lead almost. This funnel has only had powder through it and I've used it for 7yrs or so now... Any idea what is building up off the powder from use?