Sometimes steel will color your silver. It usually is a result of
runs that are too long. Unless you are using steel for hardening, you
simply don’t need runs in excess of 35 minutes.
If you have no stones, run for an hour in vibratory tumbler with
fine abrasive, wet. Rio blue clean cut is a good choice. Then back to
the steel - but for a max of 25 minutes. Alternative - run in ceramic
beads instead of steel.
The ceramic won’t fix your problem by Friday - it needs to be
conditioned for several days and after conditioning, runs are
typically a minimum of 36 hours.
If you have stones, use red or blue bristle discs (3M) to remove
color, then gold and green for final polish.
Or - ignore the color - most folks can’t discern metal colors or
don’t find them objectionable.