Art restorers in Pisa, Italy have discovered that bacteria applied to medieval frescoes that were covered in glue 50 years years can cut through the glue and reveal the painting. “Scientists from Milan University have shown that the bacterium Pseudomonas stutzeri, applied with water on cotton wool, can eat through 80% of the glue in about 10 hours. Chunks of the 14th- and 15th-century series of frescoes at the Camposanto (cemetery) were removed for repair and restoration in the 1950s” when they were covered in glue, and restorers have been trying to figure out how to remove the substance ever since.