Peppernut is pretty easily agreed upon to be the worst charm.
Here is my suggestion for a rework:
Peppernut: Gain "When you gain Spice, gain 2 Shell."
The idea here is to make it a pure positive, rather than an exchange, and to make spice runs more interesting/stronger when you get the charm.
Feel free to post your own suggestions for how peppernut could be reworked.
gain 2
, and when you gain