In this Wednesday, Aug. 26, 2015 photo, in River Forest, Ill., painting conservator Barry Bauman works in his studio cleaning a George Catlin painting owned by the State Historical Society of Iowa while looking through a binocular microscope. He's cleaned and fixed 1,500 paintings for hundreds of museums nationwide over the 11 years and he's done it all for free. (AP Photo/Carrie Antlfinger)

RIVER FOREST, Ill. - An Illinois man has spent up to 10 hours every day for 11 years cleaning and fixing 1,500 paintings for museums nationwide. He's done an estimated $5 million worth of work.

He didn't get paid once.

"Either you got to be crazy or love what you are doing, maybe I'm a little bit of both," said 67-year-old Barry Bauman, who works out of his home in River Forest, a suburb of Chicago.

He worked in the conservation department of The Art Institute of Chicago for 11 years before starting his own business, the Chicago Conservation Center, in 1983. By 2003, he had 23 employees and the company was starting to run him. So, he sold it and thought about doing conservation work for museums at a reduced price.

His wife suggested he do it for nothing.

"The minute she said it I said, 'That's right. I'm going to do this for nothing,'" he said, though customers pay for materials and shipping.

The work entails cleaning dirt and discolored varnish and fixing torn canvases and flaking paint. He sometimes retouches parts of paintings and adds newer varnish that can be reversed. One painting is typically a three- to four-month job, sometimes using a cotton swab and a microscope. He turns away paintings more than 10 feet tall, copies of paintings and ones that are too damaged.

Since announcing his effort in a 2004 letter to museums — "This will enable institutions with limited budgets to preserve paintings that are needlessly deteriorating simply due to lack of funds" — Bauman has worked with 300 museums. His 65 paintings for the Wisconsin Historical Society earned him a "Certificate of Recognition" from Gov. Scott Walker last year for donating $250,000 in conservation services.

Society curator Joseph Kapler says Bauman's gift to art, museums and the public is incalculable. The society is now using the restored work for illustrations and publications and to improve their website.

"I don't even know, is this a hundred-year gift? I don't know because I don't think there has been anything like this," he said.

Bauman has even helped discover fake paintings, like the one supposedly of Mary Todd Lincoln that for years hung in the Illinois governor's mansion. The woman's face didn't look like Lincoln, he explained, and the painter's signature of Francis Bicknell Carpenter was on top of the varnish, rather than the paint, meaning it was added later.

His love of conservation comes from a great appreciation of artists — he has a masters in art history with a specialization in Dutch Baroque paintings from the University of Chicago.

"Artists just have something really unique that cannot be taught. It's inside of them," he said. And he's worked on paintings by some of the masters — Picasso, Rembrandt, Monet, Renoir — feeling a deep responsibility to them and the work.

"They are sort of all my children," he said.

He looks after his "children" when he visits the museums, being "very critical to make sure it still looks its best ... conservators come and go, but paintings with proper preservation can live hundreds of years."

He plans to continue to do restoration until he physically can't: "Everybody comes to that moment, but I see that as a distant future moment."

News from © The Associated Press, 2015