but I’m worried it will stain if I leave it for too long. So I set up a camp chair in front of my washing machine and I’m hanging out here, babysitting the washing machine.
I've accidentally dyed stuff with hair dye e.g. skirting boards, bathroom cupboards etc.but hadn't noticed at the time. A bit bleach does the job, just wiping it over for a few minutes. I managed to get blue dye on the white painted window ledge, again a bit of wiping with bleach brought it off with no yellowing of the paint.
I would think even if the enamel/paint on the washing machine did get stained then bleach would get rid of it.