[sleep1937]

I kept 2-3 drops of mercury from a broken thermometer in a box that apparently wasn't exactly sealed. a month later most of the mercury was gone.
does that put me in any risk?
how did it vaporize if its boiling point is 356.58 º C?
if buying a sealed vial, will it have to remain close or will i be able to open and close it?

[P]

I kept 2-3 drops of mercury from a broken thermometer in a box that apparently wasn't exactly sealed. a month later most of the mercury was gone.
does that put me in any risk?

Depends where you kept the box!  Was it kept in your garden shed or was it under your pillow at night?   If it was only a few drops you should be alright  -  anyway, it's too late to worry now.

how did it vaporize if its boiling point is 356.58 º C?

How does a glass of water left on your bedside table evaporate when it's boiling point is 100C ?? 

[sleep1937]

i honesly don't know
how?

[Borek]

Evaporation goes all the time, the higher the temperature, the faster. Check out the definition of boiling point.

[vmelkon]

All liquids evaporate, specially the ones with small molecules. Oils and melted plastic probably almost don't evaporate since their molecules are gigantic and entangled together.