Can somebody help me please with the identification?

[thalassa]

Hello!

Does anybody know what the name is of these shells? And also, has anybody experience in cleaning these? I found the smaller one pretty clean on the beach(Crete) but most of them look dirty, like the bigger one and even after two days in a bleach solution, they look the same. I even tried to put one in vinegar with also no result. Any suggestions wouls be welcome!

http://www.badongo.com/pic/15570139
http://www.badongo.com/pic/15570148

[Herner]

Hi,

I think, it could be Stramonita haemastoma, but I´m not sure.

Greetings Herner

[paul monfils]

I agree with Stramonita haemastoma (Thais haemastoma in some older books).  The problem here is not that the shells need cleaning, but that they are eroded as a result of washing up on the beach and being worn down by repeated rolling around in waves and sand.  Bleach won't have any effect on shells in this condition, and vinegar (or any acid) will just erode them further.

[thalassa]

Thank you very much for your help!