Jars

There are quite some Zappa songs that reference jars:

Sleeping In A Jar
Let's Make The Water Turn Black (Not mentioned, but implied. We know from Ronnie's Booger Story and Kenny's Booger Story that they stashed away their urine in a large jar.)
The Idiot Bastard Son ("Kenny will stash him away in a jar.")
God Bless America ("the old cookie jar")
Tiny Sick Tears (Again a cookie jar is mentioned)