As long as you thoroughly flush the hydrogen peroxide out fairly quickly after using it (I shoot for under a minute) then it shouldn’t bleach your clothes. Although if it’s something really expensive I would do a test somewhere less noticeable first.

Hmm, perhaps I got lucky with my one work shirt - it was already a light red, and I didn't notice any dimming when I used a bunch of hydrogen peroxide on it to get a handful of blood out. Maybe it's just darker things?

I had an oil stain in my cupboard. It was from a bottle of oil that had some oil on the bottom of the bottle. I tried soap since I thought soap removes oil but it wouldn't come off at all. I poured some baking soda on it, wiped it with a wet cloth and it came off like nothing. I have no idea why that worked.

yeah, grease is just oil and the best thing to remove both of them is dish soap in warm water.

what about milk for ink? Ive not heard of that and cant reason out why it might work.