Removing stains on baby clothes?

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I’m a first time mom so forgive me if this is a stupid question but what’re some tips and tricks for removing formula/breast milk stains out of baby clothes? Also, poop stains (😂)? I notice her white onesies have formula stains. I don’t like white clothing so I never buy any for myself, therefor I don’t know how to go about removing the stains. 🤦🏻‍♀️