I crashed my kite bad the other day in the ocean. Had to roll it up while I was out there and then swam in. Long story don't ask. I folded up my kite with minimal sand in it. But it was totally wet with salt water. Left in car for a day and now a minor rust stain???
How can I remove this?
I would not worry about it. The rust stain won't harm the kite at all.
Anything you use to remove it will damage the fabric.
A kite that is wet with salt water will not rot or get mildew. However salt buildup could be abrazive.
Good Idea to rinse off the kite if you have a place to dry it well afterwards. Otherwise just dunk it in the ocean next session and that will get any salt patches off.