A painting that was once a masterpiece can lose its ___1___ after centuries of exposure to the elements. Its true hues may become ___2___ by grime and even buildups of salt. But now researchers in Spain are cleaning works of art with unlikely allies—bacteria.

Art restorers had been working on 17th century frescoes by Antonio Palomino in the church of Santos Juanes in Valencia. The paint was covered by salt crystals and gelatin glue. So the researchers headed to Italy to learn about a glue-munching bacteria. Then back in Spain, they trained a strain of Pseudomonas bacteria to preferentially ___3___ salt blooms.

They also figured out a new way to apply the bacteria. The scientists trap the bacteria in a gel. This way, the single-celled cleaning crew can destroy the salt layer with no moisture penetrating the murals.

When the gel is cleaned off, the surface is quickly dried, leading to the ___4___ of the bacterial assistants. The researchers presented the results at a seminar in Spain.

They’re now working on ___5___ the technique, so that it can be used with paintings on various surfaces. And thus bring dulled and damaged works of art back to life.
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