Should I wash the outside of a pecan shell before I get them cracked?

You can rinse the pecans if you like, but make sure to get them dried thoroughly before taking them to be cracked. Let them dry on newspaper in a thin layer before bagging them back up again. Try not to keep them too long in the wash so that they don't get overly soaked and don't use detergents. If soaps seep inside the shell, the kernels can absorb the flavors very easily.