It's about 3 a.m. and I think my mind has went out on me.
It's easy to remove an object from a list/array when you know what that object is:
<<set $foo = "foo">>
<<set $bar = "bar">>
<<set $baz = "baz">>
<<set $inv = [$foo, $bar, $baz]>>
So, $bar is removed. No problem.
However, what if all objects have the same name (e.g., $item)?
I'm sooo sleepy right now that's about as well as I can pose my question. I'll probably wake up tomorrow and figure it out, but I thought I would ask just in case.