<HTML>In a message dated 5/5/01 10:52:18 PM Central Daylight Time, diskladame@provide.net (Z! Reinhardt) writes: <BLOCKQUOTE TYPE=CITE style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px; PADDING-LEFT: 5px">The 40% solution can be found at beauty supply shops. </BLOCKQUOTE> Sorry, that is a common misconception.  "40 Volume" is not the same as 40%.   I honestly forget what the meaning of "volume" is for these products, it's been a long time since I did that kind of work but I remember being misinformed in the same way back then.  If you were to put a solution of something on your hair that is really 40% Hydrogen Peroxide (H2O2), it would chemically "cook" it to the point of destruction and your scalp would be burned severely as well. In a nutshell, the worst of the discoloration of ivory is in the oxidized surface.  Often a simple cleaning, sometimes with a mild abrasive followed by buffing will renew their color sufficiently.  If the cleaning with a mild abrasive isn't enough, using the 35% H2O2 solution in repeated applications under either natural or artificial ultraviolet light will lighten their color. You have to specially ask for this chemical because it is very strong and potentially dangerous.  Whatever the beauty supply house has, even its strongest is nowhere near this strong, I'm guessing 10 or 12%.  It is the same solution as the 3% H2O2 that you may have in your medicine cabinet, just more than 10 times as concentrated.  H20 is water as you know it.  In H202, the extra Oxygen molecules are a classic example of the often talked about "free radical".  The H2O2 molecule wants to rid itself of that extra oxygen molecule, so it will give it off to nearly anything. It is a very unstable compound that wants to stabilize itself into just plain H20.  That extra Oxygen molecule will *oxidize* anything it can.  When the concentration of H2O2 is very high in a solution, it becomes a very powerful corrosive or catalyst.  Yet, it really does take this much chemical strength, plus dangerous and harsh ultraviolet light in *repeated* applications to really have a significant bleaching effect on ivory. Consider this when weighing the factors about how much this should cost and which precautions should be taken. Bill Bremmer RPT Madison, Wisconsin Bill Bremmer RPT Madison, Wisconsin</HTML>