How to clean shells

[faye]

i was told by a malacologist that shells should be soaked in fresh water to remove salt, as over time salt will erode the shells. he suggested an hour soaking for tiny shells and overnight for the larger ones.
i am assuming that the bleach treatment is for xtreme makeovers where debris or mud etc, needs to be removed.
i was just looking at some shells today, from india, that need the heavy treatment and didn't know what to use, so thanks for that info.