Always dispose mercury separately!
Never mix up mercury with other waste. If the mercury is already mixed with other material for example with sweepings, which has been swept from the area underneath the laboratory benches then dispose as "mercury containing sweepings" in a separate bottle. Dispose elementary mercury separately from compounds of mercury. It may happen that elementary mercury can be recycled (which is done by vacuum distillation).
Keep the weight of the waste low! If a mercury thermometer has been broken you may cut off all mercury-free glass with a glass cutter and dispose this a normal glass waste. Only the mercury-containg glass needs to be disposed as mercury-waste. But look carefully: If the mercury has been sprayed you may find lots of very small drops all over the glass surface.
Never spread any "helping" compounds onto spilled mercury!
Sulfur is without any effect and costs twice: First you have to buy the sulfur powder and second you have to pay also for the waste sulfur. Zinc powder is right the same! Iodized active carbon only helps for mercury vapors, with liquid mercury it does not do anything and the only effect is a calamitous daub.
If mercury is spilled over a wide area on the floor it is best to sweep it up. For a smaller area use a flat brush. With a plastic shovel at hand you may proceed to brush it onto the shovel. Use a funnel to decant the mercury into a separate bottle. Alternatively you may also use a sheet of zinc. The zinc sheet works only after having been etched with diluted hydrochlorid acid. Bring the etched sheet into contact with the mercury drops. The drops will "jump" onto the zinc. Look at the picture to get an impression how this works.
The arrow is pointing to a mercury drop which is just jumping onto the zinc. The absorbed drops may be shaken into a separate bottle. The zinc surface will become amalgamated and in this situation it is not oxidized as easily as pure zinc. But from time to time a reactivation with hydrochlorid acid is still needed. The zinc sheet may be used lots of times but on using it, it will slowly downsize.
Mercury has a poor reputation. The H-phrase 330: "Fatal if inhaled" is a part of the GHS-labelling. Nevertheless you will not perish at once, if mercury is spread anywhere. The reason is that mercury has only a very low vapor pressure at room temperature and moreover the vapor is much heavier than air and will fall to the floor. However, spilled mercury always must be removed completely, because continous breathing of mercury vapors even with low concentrations may cause diseases.