Ever wonder what Vietnamese restaurants do with the bones left over from making pho?

At Rice Paper in Chinatown, the bones used to be given to family and friends. Now they’re given to customers.

At fancy restaurants an order of roasted bone marrow can sell for $20 or more. Rice Paper’s version is free.

The bones at Rice Paper are boiled, not roasted. Simmered with salt and sugar for hours, the bones are then removed from the pot and more seasonings added to the broth for pho. The bones become a dish in themselves.

Huge joint sections are used, some about the size of a toddler’s head, with meat and tendon still attached. It’s not the prettiest, most appetizing- looking appetizer. And bone marrow, which is mostly fat, is not very healthy. But it’s free. It’s a lot of food, and for those who like bone marrow, it’s soft, gooey and tasty.

“It’s called xi quat. It’s just bones that you used to boil your stock, and what’s left over, you eat that,” said Rice Paper owner Quynh Mar Chong.

The pho broth usually is made once a week, on a Friday, and a sign goes out front on nights when the bones are served. A notice also is posted on Rice Paper’s Facebook page.

“Most restaurants don’t use a lot of bones like we do. It’s because we use so much that we are able to give it away. It’s enough for everybody,” Chong said.

The pho recipe is the same as it was when Chong’s parents owned the restaurant, formerly known as Pho My Lan.

The bones start boiling at about 10 a.m. and are ready to be removed by dinnertime. Diners in the restaurant by 6:45 p.m. on pho broth nights can get the bones.

One bone can be a whole meal, so you have to order something before you get your free soup bone.

The bones are big enough that you can use a straw to sip out the marrow, which coats your mouth. You’ll taste beef and fat, with a little sweetness from the sugar used in the broth.

An extra $2 buys a plate of lettuce and herbs to eat with the marrow.

Chong likes to scrape off some meat and tendon and wrap it in Thai basil or other herbs.

Or, dip the meat and tendon in a mix of soy sauce, Sriracha, the restaurant’s chili oil and a little bit of lime.

The meat is soft enough to scrape off with a spoon or chopsticks, but “people do pick it up and eat it,” Chong said. “They’ll clean it.”

Web producer Craig Gima tries out new foods in a video and print series every other Wednesday. Dare him to try a really scary food: cgima@staradvertiser.com.