It's not rocket science, is it?
No, indeed, but if you take a shaker (or a salt or pepper shaker etc.) in your hand, you will naturally use it like this, from top to bottom:
Naturally, but it is a bad way to do it, because by doing so, the powder contained in the shaker will pack itself towards the outlet, and end up clogging the shaker.
How to do it?
The trick, and the good gesture with this kind of utensil, is to handle it "flat", like this:
This way, the powder inside moves in the shaker, doesn't clog the outlet, and is much easier to distribute.
Humidity, the enemy of powdered productsIn
the same spirit, if you use a salt shaker above a dish that is cooking, and inevitably releases some steam, you will inevitably moisten the salt contained inside, and as you go along this moistening will increase until it more or less clogs your salt shaker, and this even if you hold it the right way round, i.e. flat, as you know now ;-).
Can you avoid this?
Not really, in fact, even if you do it quickly, your salt will get a little bit wet, and over time...
It's inevitable, but it can be corrected : You just have to put your salt shaker in a soft oven (we say "falling"), for a while, to dry again its content. The best way to do this is to put it in the oven after cooking a dish, remove the dish, turn off the oven, and put the salt shaker in. Leave it for a good hour, with the lid off if possible, until all the salt in it has dried completely.
To sum up: 1) To use a salt shaker, hold it "flat". 2) To dry a clogged salt shaker, put it in a low oven (hot, but turned off) for 1 hour.