If it were me I wouldn't drink out of them anymore.

It's very dry here and wood doesn't hold up well on its own. We use mineral oil on all of our kitchen wood stuffs. You can find food grade mineral oil in most kitchen stores. Just slather a bunch on with a brush or towel, let it sit for a half hour or so, then wipe off the excess. Wait a day or two, then wash in soapy water. Repeat as needed.