Found some rubbers at the guitar shop today.
I went in looking for alternatives to my old faithful 3mm Big Stubby. I love the way my picks feel, and I love how they sound until I use a tone that brings out the attack. They're big and strong enough to generate their own little notes every time they hit a string. This is especially irritating with the bridge pickup. The pick acts as a new fret, an octave above the normal range, and goes "clink" every time I pick a note.
Playing with this pick is a strange experience. The strings cut into it a bit, so it sticks longer than I'm used to. The tone is unique but definitely not what I'm going for, although I bet it would sound great on a bass.
I remember using Gator Grips when I was a kid. I'll give those a try again. Seems like a softer material that might reduce clink.