We have just taken possession of a group of hand painted back drops that are somewhere between 70 and 100 years old. They hung in a neighboring Masonic Lodge for all that time. Do I dare try to clean these or should I just hang them in their new location and enjoy them? There are also some small rips or tears is some of them. (No holes). What is the best method to patch these. Each of the 5 painted canvases is approx. 12 feet tall x 20 feet wide. Any and all suggestions are welcomed and appreciated.
Conservation of old materials is a specialist area, if in doubt do nothing. Your local museum might be able to advise. At a guess: keep out of bright sunlight, control humidity, don't fold (perhaps don't even roll up). Remember Hippocrates: first do no harm.
Remember that light has an adverse effect on many materials -- that's why museums often prohibit flash photography. Keeping your backdrops out of the sun will help, but if you're planning on using them in photo shoots, be aware of the damage that repeated exposure to speedlights and other very bright light sources could cause to both the paints and the fabric.