I cut the bands of interest after loading the proteins to the gel but I would like to keep them for a further MS analysis. Should I leave them with water? acetic acid solution? some specific buffer?
Another option is to equilibrate the stained gel with 5% glycerol and then dry it o/n between two sheets of cellulose acetate (you can get the sheets and the frame from BioRad, but the former cheaper in household stores, they are used for covering jars of homemade jam). Then you can cut the band from the dried gel and store it at -80 °C in a suitable vessel, w/o solvent. This would avoid protein degradation as much as possible.
The dried gels also keep very well in a lab book, btw.