Stem bleaching question.

Before you bleach stems wipe them down with alcohol to clean off any waxes or oils left from handling. I use a fairly large container and suspend the stem in the bleach using a pipe cleaner. It seems to me that the quality of the rubber has a lot to do with what they look like when removed from the bleach. Good rubber will come out with a sort of satin look to them,cheap rubber stems sometimes look as if they were sandblasted. A lot of cheap stems will have impurities in the rubber which can increase the pitting or show up as speckles after sanding and buffing. Cover all metal parts with Vaseline. Plastic inlays generally won't be affected by the bleach. As Whitewolf said,any rubber stem that has been bleached will need to be shined up,some requiring more work than others. Rinse the stem with cool warm water and soap and pipe cleaners to remove bleach. Do not use hot water on a rubber stem.

Unless the stem is heavily oxidized there is no need to use the bleach. Wet sanding with Micro Mesh or a good wet/dry sandpaper will do the job.

I am not particular fond of using other "chemicals" than alcohol on stems. The composition of stems seems to vary so much that you get much varied results.

Clean/rub toothpaste with micro fiber pads or a Mister Clean Magic Eraser, then rub down with mineral oil then polish with a buffing wheel and Carnuba wax, that's how I do it

Are you bleaching to remove oxidation?