Polishing abalone shells

Has anyone tried cleaning and polishing the outside of an abalone shell to make it look like the inside? Is it worth trying or just a huge labor-intensive job. Any advice would be great. I've been soaking them in bleach and scrubbing them with out much success.
Thanks!

From watching/talking to some Paua (NZ abalone) artists in New Zealand a few years ago, it's sounds like it's both labor intensive and dangerous.  In order to get the proper effect, you need to polish the abalone down to a very thin shell which is hard to do evenly.  On top of that the dust created by polishing the abalone is apparently dangerous to breath in.  At the artist's studio they had an acrylic box with attached airtight gloves that allowed them to work the paua on the grinder/polisher inside the box.  It looked a bit like a biohazard handling operation.

Brian

Muriatic acid mixed about 25% with water (mix acid to water!), which can be bought at the hardware store for cleaning concrete and pools,  Cover the inside of the shell with vaseline and soak in solution.  The more you soak, the more stuff comes off the top.  Acid wears out after a while and needs recharging if you want to soak more.

Muriatic acid mixed about 25% with water (mix acid to water!), which can be bought at the hardware store for cleaning concrete and pools,  Cover the inside of the shell with vaseline and soak in solution.  The more you soak, the more stuff comes off the top.  Acid wears out after a while and needs recharging if you want to soak more.

The acid cleans the red exterior of the shell.Dry thoroughly then coat with your favorite clear finish to bring out the beautiful red color. A non yellowing acrylic is a good choice. Both sides can be clear coated for a shiny finish.The red shell is prized by the native americans and was traded widely.
 As a old time lapidary I would not try polishing without dust collection and wetsanding ability. Years ago I met a few "Hippie" jewelers who developed lung disease (very nasty) at a young age. It's a lot of work to polish a shell.You have 1/8"-1/4" of shell to grind,fine sand ,then polish on a buffing wheel.

i've seen them done the muriatic acid way and they came out real nice.

I have used a die grinder before with a 1/2" steel carbite bit to take the outer shell down to the mother of pearl but it is a real pain is the a#$ and takes a while since the abalone shell is very hard.The first time I did it I wore a 3m respirator and long sleeve shirt gloves etc..Also the dust goes everywhere... you have to be very carefull like everyone else has said the dust is very toxic and you should not breathe , I have also been told to keep it off your skin. It can irritate the crap out of it and cause a rash. If you plan to grind and polish you should do it in a enclosure like a sandblashing box or something of that nature where you aren't in direct contact with the dust. I have found that this way works the best. Overall I have had it turn out very nice but its very labor intensive. What I usually do is just put a wire brush attachment on a drill and take off all the growth off the shell until its the red out side color, wet sand the inside and spray with a clear coat (non yellowing). I usually end up putting them out in the yard or in the house depending on the condition of the shell.

Yep, all of it is true. It is hard work and toxic to breath or otherwise injest. I have used a dremmel tool and mask for some smaller pieces I used to make some jewlery. If you know someone with a sandblaster box/booth that would work best, or just use a good grinder and a good mask and eye protection.

I just soaked a bunch in muriatic acid + water for about 20 minutes and they came out bright red...a little clear wood finish and they're beautiful.