This painting suffered from a cardboard wood pulp based mount. Over time this had introduced acidic components to the paper, causing staining and a deterioration of the paper strength. Tape residue was along the perimeter. 

The painting was soaked in chemistries to remove it from its mount. Tape residue was carefully removed. Another round of chemistries lifted and neutralized the acid stains. Blotters were then used to simultaneously dry the paper and press it flat. 

This watercolor was executed by Willam M. Hannah (1855-1927) who was originally from Massachusetts.

Before and After.