You have to get the incentive right.

Don't have TSA do it. Have either the USPS or FedEX do it. They could grow their business enormously, since some of this stuff may have notable sentimental value, and customers may pay a premium NOT to have the stuff confiscated. They could even hire someone to do a "pre-screen" - so that you can find out what will fail, and arrange to ship it. They're already in the shipping business, so they know the ins and outs.

Final option for some stuff - a "charity deposit box" for stuff that won't pass, but is not worth shipping.

Done properly, this is a money maker for the shipper, and gets a whole raft of work and heartache (taking the little girl's baton) away from the TSA. Should speed up lines, too.
Taking the scut work away from the TSA would let them concentrate more on real security, and not hiring people to take away your nail clippers.