I’ve used my non toxic washing up liquid neat on the stain and leave to soak in, then hand wash, repeat if needed, then into the washing machine
Bicarbonate of soda, lemon juice and vinegar
Ecover do a stain remover which works fine for me, but also tried with washing up liquid or hand soap and not had any issues x
I use soap nuts, white vinegar, essential oils
Leaving it out in the sun works wonders for poopstains!
I washed with normal hand soap on sink first then pop in wash works wonders