What oil?

[marlo]

See discussion on use of oils on shells at:

<a href="http://z14.invisionfree.com/Conchologist_Forum/index.php?showtopic=333" target="_blank"><!-- m --><a class="postlink" href="http://z14.invisionfree.com/Conchologist_Forum/index.php?showtopic=333">http://z14.invisionfree.com/Conchologis ... wtopic=333</a><!-- m --></a>

I agree with Dave regarding cowries, assuming they are in fine to gem condition.  If you have cowries that do not have their natural glossy shine, and you keep them on display, then you might want to use an oil to bring out color and make them more appealing.