How do they clean the whole interior of Grand Central Station in NYC? Ceilings, walls, and all.?

Scaffolding. The major clean-up of GC was completed a few years ago and, WOW, what a difference!

You should be able to find info about it by doing a search on "Grand Central Station refurbishing" or something such as that. Or, it might be included in a Wikipedia article on GC.

What in the world makes you think that they CLEAN Grand Central Station?

I mean, sure, they sweep up the litter and debris on the floor almost constantly, but the walls and ceilings probably haven't been cleaned since the Nixon administration, and if they do it at all, it's probably once every ten or twenty years or so.

Generally speaking, the entire infrastructure in New York City is maintained with a policy of benign neglect, aka "If it ain't broke, don't fix it," especially now that we're in a recession and there's just no money available for such niceties as cleaning walls and ceilings.

Good luck!... ☺

http://www.grandcentralterminal.com/ is the only site I know.

The ceiling is not that high (about 125 feet or 13 stories) so a lift will do.

Are you in New York? Friday at 12:30pm will be a free tour.

Look on the site for where to meet and you can ask some questions.

One mall i work at years ago had one so they could change the bulbs that blew.