# What is the grey film/black sludge from mercury? How to remove it?

How to remove it? Any other simple method apart from distillation.

I have a small container of mercury that I’ve collected over the past decade. I opened the container after a few years now and I noticed that there is a grey coating on the surface of mercury. Also there is a black powdery deposit at the bottom. It sticks to the bottom and sides of the plastic container.

• Plastic containers are not air-tight, and if you stored mercury in a place with even minor presence of active gases (nitric acid or bromine vapours), , it might react. In this case you should dispose of the contamination very, very carefully as it might be very dangerous shit. Metallic mercury is billion times safer than most mercury compounds. – permeakra Sep 3 '17 at 7:38
• There is also chance that the mercury you stored was contaminated with other metals. In this case they might react with air, forming oxide powder. If you are lucky, they might dissolve in acid. However, the resulting solution must be assumed to contain mercury, i.e. considered a toxic waste. – permeakra Sep 3 '17 at 7:40

That said, if distillation is out, then try bulb-pipetting from the center of the mass of mercury to avoid some of the surface contamination. Avoid dropping the mercury when lifting the pipette, since $\ce{Hg}$ is so dense it tends to run out as soon as lifted. Ideally, work in a hood with a large tray with raised sides underneath the apparatus.
Better, get some gallium if you want to play with a liquid metal, and don't need $\ce{Hg}$ to make Grignard reagent or other esoteric substance.