Ok, Wishing you the best with the remainder of the Flow Frames,
I completely understand, mould really is not something you would want, ensuring that the Flow Frames are kept in a cool dry location will be beneficial. For drying you will need to keep them out of direct sunlight, under a tarp, or in a shady location will be best. You will want to ensure that moisture is no longer present. They are quicker drying, leaving the Flow Frames in the open position, as they are less likely to trap water in cells.
Do keep us update with how you progress with this.
–Kieran (Flow Team)