I've an old berghaus waist pack I'm thinking of resurrecting but the PU layer on the inside has semi flaked/peeled off. Is there anything I can do to stop it getting worse or better still improve the bags waterproofness? (Not sure that's a proper word) Options so far thought of A. Use a pack liner of sorts. Seems the easiest but might not fit with how I use the bag and still allows the bag to get soggy. B. Waterproof PVA glue, thinned and 'painted' on to the internal surface. C. Dilute silicone sealer applied to the outside of the fabric. Any help or ideas welcome.