The colder the water the lesser the chances of indigo transfer, heating up the dye and causing friction loosens the cotton fibers thus lets surface dye bleed. A paper towel and cold water and you blot it, you can add a little twist to it when blotting to create a little friction to help remove whatever is on your jeans, but if you start to see dye transfer stop. You could also spot clean with a stain remover and then soak them using a method, that through trial and error, I have pretty much perfected. I'm fairly positive Gustins are Sanforized so soaking them will essentially have no effect, especially the way i do it. No indigo loss and your pants will be clean, you will lose some starch though if they are still super raw at the moment. PM me if you're interested and want details as to how exactly to do this.