Don't push too hard!!!!
Fabric aircraft should be cleaned regularly. Cleaning regularly will help avoid using aggressive cleaning methods to bring it back to its original finish. These paints are very porous and can be damaged much easier than traditional aircraft paints.
With many years of experience restoring fabric aircraft there are two mistakes I see made. The first is not keeping the aircraft in a hanger. The UV rays can deteriorate the paint quickly. The porous paint lets contaminants stick to it easier which is a recipe for the paint cracking. The second mistake is cleaning the fabric panels with simple green. The dyes in cleaners can stain the paint and not be removed. This is why we use cleaners with no dyes in them.
Now when cleaning the surface we want to use light pressure. If you push too hard you run the risk of damaging the fabric. Although not likely the surface is not like typical aircraft aluminum skin. Be cautious.