Cleaning innie belly button

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I just cleaned out my 4 month old baby's belly button and OMG I nearly died. It had this dry dark scab like particles in it and the smell was 🤢. I removed it using rubbing alcohol and a cotton swab but now it's red and I'm not sure if this was the way to go. How do you clean your baby's belly button? I have an outie so cleaning was never difficult.