In brief:
1. Washed the shell out after removing the meat
2. Let dry outside for at least a month, not in direct sun (these were sitting around for a few months before I got to em)
3. Scrubbed exterior with steel brush UNDER RUNNING WATER. You do not want to be breathing any calcium carbonate dust you may create. Wearing a properly fitted N95 respirator is ideal.
4. Wash and dry interior. Then coat with vaseline to protect the nacre against the following acid treatment.
5. Treat exterior with relatively concentrated hydrochloric acid. You can buy it from hardware stores like Lowes, it sells under the pre-IUPAC name "Muriatic Acid". The one I used comes in at <25% according to MSDS and did the job. Other manufacturers that retail commercially provide HCl in the 30s, but you don't need reagent grade 37% to get the job done. I used it undiluted, but if you dilute concentrated acid in a container, always add acid to water and never water to acid. Wear personal protective equipment when handling concentrated acid (gloves, safety glasses or face shield, full length clothing and closed-toe shoes), and treat with lots of ventilation - don't breathe fumes. Neutralize acid with baking soda, apply it until foaming stops. Otherwise flush with lots of water to dilute. For this shell I did two pour-over coats at 5 min per coat. Rinse shell and do as many coats as you need to get the shell to where you want it.
6. After thoroughly rinsing your shell, take a steel brush to it again under running water to scrub off any remaining crud.
7. Wash off vaseline from interior. Scrub nacre lightly with scotchbrite to clean and help bring out irridescence (green scotchbrite does the job, I use the no-scratch blue ones to start with then work up if I want to)
8. Let dry
9. Finish exterior and interior (to bring out shell color and irridescence) however you like. I personally give the exterior and interior a light but thorough rub-down with mineral oil because I have it handy. You can use lacquer or other finishes. Some prefer the finish left by a matte lacquer over the glossier finishes left by mineral oil and others.
10. Enjoy :thumbup:
