I'm trying moist stratification for the first time, using the damp paper towel in Ziploc bag method. I stratified the vegetable seeds two weeks ago. Despite meticulous attention to sterilizing the materials, several of bags now have light brown spots on the paper towels, measuring about 5-7 mm (3/8") across. There doesn't appear to be any hyphae, and the seeds look OK. So now I'm wondering: 1. Is this mould? 2. If so, can I rescue the seeds, and what can I do to protect the apparently unaffected bags? THANKS!