How to make a coconut oil and peppermint oil for hair mask. Use a peppermint and coconut oil hair mask for growth. Leave on for 30 minutes or overnight for deep conditioning. A DIY coconut oil hair mask is great for dandruff or for dry scalp. This peppermint hair mask also has coconut oil and raw honey. Coconut oil hair mask is great for dry hair or for damaged hair. It helps smooth your hair and make it softer and shiny.