Every year, the massive blue whale that hangs in the American Museum of Natural History's Milstein Hall of Ocean Life gets a bath. Or rather, gets vacuumed. And this year's cleaning will take place on Tuesday and Wednesday, May 30th and May 31st, if you want to see the oddly satisfying event live.

The Exhibition Department staff uses long-handled brushes and vacuums to get the past year's worth of dust and dirt of the whale, which has been a centerpiece at the museum since 1969. Some fun whale facts:

This is the largest model of the largest creature that has ever lived on Earth

It's made of fiberglass and polyurethane

It weighs 21,000 pounds!

It's 94-feet long

The model is based on a blue whale found in 1925 near South America

The model cost $200,000 at the time, and took two year to build

The Whale (it's official name) replaced a 76-foot blue whale that was installed in 1908, which "did not bulge properly," according to a NY Times story (PDF) from 1968.

The Times also reported that "the boss of the crew, Tom O'Toole, a man who walks the girders of skyscrapers without visible fear, gave in and took some tranquilizers during the day," later saying, "This was my first whale and I hope it's my last one."

If you can't make it, the museum will have a live broadcast of the cleaning streaming on Facebook for some of the time. Click through the above photos from a previous year's cleaning to see that before/after goodness.