Picked this up this nice Hamilton military watch last week which think was very cheap It had a damaged crystal running 2 seconds a minute fast. Was going to send off for a service (which I will in a few weeks) since I was getting a new crystal i looked at the mainspring and there was some dirt between the coil gave it a light blast with some air now running about 10 seconds a day fast New crystal arrived this morning just fitted but in my rush forgot to make sure it was dust free so can see some dust under the crystal cant get the dam thing back off just have to wait for the service Edit managed to get crystal off now nice and dust free