Hello, I have a vintage japanese silk kimono white wedding dress possibly from the 20s that has a few unknown slightly yellow stains on it after having been in storage for a few years. I'm looking for advice on removing them. I tried warm water, but the scrubbing action seemed to begin to damage the hand embriodery. Most remedies I could find online seemed tailored to specific types of stains, but I don't know why it became discolored in storage. Any help would be appreciated.