To send a fuel pump back for warranty reasons, the gal at the post office advised to use their competition to send it.

Has anyone else sent one using the post office. It would be handier approximity for me, than Fed Up, or UPS.

Clean the fuel out and wrap it in a turkey oven bag. The turkey bag will keep it from smelling like gas. Then use USPS and don't say nuthin...

Or put it inside a plastic mayo jar.
I once sent one to Belgium and it was not sealed well enough. It took them 3 months to return it and said it could not be shipped air. Ship it ground and there is not a problem.