How long should I leave the basma on my hair, and how do I rinse it out?

The processing time can vary from 1 to 3 hours, depending on the depth of colour you want and your hair's characteristics. For a subtle tint or on very porous hair, 1 hour may be sufficient. For a more intense, darker result, you can leave it on for up to 3 hours. You can cover your hair with a shower cap during this time to keep the paste moist and prevent drying.

To rinse, first use lukewarm water without shampoo to remove the bulk of the paste. Massage your scalp and lengths under the water stream until the water runs mostly clear; this may take several minutes. A small amount of leftover greenish or bluish tint in the water is normal. Afterwards, you can use a mild, sulfate-free shampoo to cleanse your hair thoroughly. Avoid harsh clarifying shampoos for the first couple of washes, as they may strip the colour slightly. The colour will continue to oxidise and settle over the next 24–48 hours, so the final shade will appear slightly darker after your first wash.