If you use steel wool for silver recovery, there are three things to think
about:

1.) IIRC, you must use very pure fresh steel wool for the process to work.
You cannot be sure the stuff from the supermarket or hardware store is
fresh enough. So the best bet is to buy the Kodak cartridges. Can you
afford them? Can you afford the shipping charges back to Kodak's refinery?
Can you afford the assay charges? Will the value of the silver pay you for
the trouble and expense of running the system, much less make you any profit?

Back when silver was around $40/troy ounce, recyclers were knocking on my
dentist's door to get his used fixer (his techie processed X-Ray film in
the office lab). These days, that is at an end. While my dentist has not
replaced the X-Ray film and processor yet, he is seriously considering
going over to a fancy detector and computer system and eliminating the
film altogether. Apparently the system, while more expensive initially, is
more sensitive (lower X-Ray dose to patient) and less trouble than
maintaining a wet process development system.

2.) Unless you reject several gallons of exhausted fixer per day every
day, the steel wool process does not work well. If the fixer is not nearly
exhausted, you will not get enough silver into the steel wool to interest
a recycler.

2a.) If you cannot interest a recycler in your steel wool contaminated
with silver, what are you going to do with it? If you are in this for
ecological reasons, you better have a good solution for the disposal problem.

3.) Will your sewer system allow large amounts of iron to be dumped down
it? I.e., is the ecological benefit of removing the silver from the
effluent greater than the ecological harm of dumping the iron into the
environment and also dumping the large amounts of water required to dilute
the iron?