Be careful not to remove the brown skin on the pit – that’s the seed cover.
Some avocado pits are slightly oblong, whereas others are shaped almost like perfect spheres – but all avocado pits have a bottom (from where the roots will grow), and a top (from which the sprout will grow). The slightly pointier end is the top, and the flat end is the bottom. In order to get your pit to sprout, you will need to place the bottom root end in water, so it’s very important to figure out which end is the ‘top’ and which is the ‘bottom’ before you go piercing it with toothpicks.
Place seed half-submerged in a glass of water
And set on a quiet windowsill with sunlight. It’s helpful to use a clear glass so you can easily see when roots start to grow.
Many guides say sprouting can take anywhere from 2-4 weeks, but in my experience, it usually takes at least 8 weeks to get a sprout,
you can leave the pit out aslong as it doesn't dry out to much, you must keep the conditions right.