I find sunlight works really well on lots of different stains. Summer is the best for it but even a bright winter day can get enough UV to reduce a stain right down. Make sure you use a cold wash so the heat doesn't set the stains in and use either powder detergent or add in some stain removing powder as the stain removing stuff is only in dry detergents
I soak them in Napisan and hot water for an hour or so before putting in the wash, works 9 times out of 10 and can get it from Asda
I just wash as normal, and then hang outside until the stain has gone 😊
I try to find non-toxic/EWG rated detergents as my LO is only 8 week and it’s been tough. What works 9/10 times is I do a soak in ECOVER laundry bleach powder (I get it in Sainsbury’s) rinse then spot treat with the Attitude baby leaves stain remover which I order online before throwing it in the wash on a normal cycle x