Any decent performance space owns at least one concert grand. It is common practice to cover a piano between uses. The main reason to do so, of course, is to prevent it from gathering dust.
But there is more to it than keeping it clean – and who likes the sight of passing a finger over its surface and having a smudged finger ? Covering a piano is not only a matter of cleanliness but of protection as well. Dust is comprised of many particles, some of which are abrasive and therefore capable of scratching it, even its most finely polished surfaces. Piano covers are indispensable in institutional settings, and should not be overlooked in home use, especially for instruments seldom played or exposed to less than ideal conditions.
But there is yet another reason to have them covered. From baby grands up to nine-footers, there are covers designed for all models, and available in different widths as well, some simply draper over the top and sides, others falling straight down to the ground. The latter are markedly better in that they enclose the moisture within the instrument. This also applies to uprights, and there are covers specially made for them.
Now that we know the why, next comes the how. The video below demonstrates this. Pulling it off the instrument and folding it on the ground is clearly not the right way, for one you will get hopelessly entangled in it and make it even bustier in the process. Because covers are made to keep dust away, it only stands to reason that they too should be kept as clean as possible. As seen, it should always be left on top of the lid and folded twice over on one side, twice on the other, and finally rolled up (or folded over, whichever) from the outer end towards the keyboard. To re-install it, the same procedure is to be followed, in reverse order.