Can used filter-inserts be used for anything?

Question

Such as, would the crud-encrusted filter fiber supply nutrients for a tank with just plants in it? Should I remove the carbon out of it?

Or should I just toss it in the trash?

Answer 1

Rinse them out well with a strong water spray (kitchen faucet with properly applied thumb pressure) and reuse them.

Repeat until the mesh actually breaks and the carbon starts to break out, then toss it & replace with a new one.

Answer 2

if its really bad toss it in the trash and if it isn't wash it out :)