A small idea based on previous posts on the topic of disposing of mercury-containing waste.
Pick up an old car battery.
Open it up. Neutralise the acid and pour it down the toilet. Avoid pouring away the solid white PbSO4.
Take out some of the lead and keep it for making NaNO2.
Pour in your waste and cover with powdered Cu, Ni, Zn, or S.
Screw the top back on. Make sure that lid is really screwed on tight and will not leak.
Shake the battery about until you think that the Hg is definitely amalgamated.
Chuck it in the trash.
Is this a good idea? I thought this might be ethical because car batteries contain heavy metal waste and so will hopefully be appropriately disposed of down at the trash plant. But I don't want to expose trash workers to mercury if they open up car batteries to recycle the lead.