Reshaping or resizing the Jim Dunlop 9073P Ultex Thumbpicks is a bit of a challenge due to the tough Ultex material they're made from. Our research suggests they tend to run smaller than you might expect, which can be a bummer if you've got larger thumbs.

The tricky part is that Ultex is pretty heat-resistant, so usual tricks like using hot water or a microwave won't work. You'd need to heat them up to about 425 degrees Fahrenheit to get them to bend, which is way hotter than boiling water.

Some folks have had luck by gently warming them in an oven, reshaping carefully, and then cooling them in cold water. But, it definitely requires patience and a steady hand—there's a risk of damaging the picks or burning yourself.

If this sounds like more hassle than you're up for, it might be worth checking out other sizes or brands. A snug fit can really affect comfort, especially if you're playing for long stretches. While these picks do offer a bright, clear sound, the fit might be too tight if your thumb is on the larger side.

You could look for an extra-large size if that's an option or explore other brands that provide a similar sound with more sizing varieties.

In short, while the Dunlop Ultex Thumbpicks are great for sound and durability, adjusting their size isn't easy and comes with some risks. Think about whether the excellent tone is worth the fit issues, and don't hesitate to consider alternatives if needed.

Comfort and playability should always come first, particularly if you're playing regularly or professionally.