Wes Stewart wrote:

One legitimate use for steel wool was what we used it for as kids.

When the cops cited us with a repair order for a too loud exhaust
system on our hot rods, we would stuff steel wool up the pipe and
secure it with a rusty nail in cross-drilled holes.

We would then find a handy cop and ask him to sign off that we had
fixed the problem. He would usually ask us to rev up the engine and
we would hope like hell that the steel wool didn't come flying out at
the wrong time. I think most cops were on to this but they played
along.

Here's a ham-radio related use. I've got a bunch of it stuffed into the
ends of the buried PVC pipes carrying my feedlines into the back yard,
in an attempt to keep the rodents from using it as a highway. Seems to
be working so far. . .

Roy Lewallen, W7EL