Can someone please help me my daughter has flicked a diamond earring out of her ear and ith has gone down the sink. We can see it but I dont know how to ger the bottle trap apart. It has a groove like a the top of a screw only much bigger on the very underside of the flat bottom of the trap. The trap is one of the chrome ones that looks nice. I would be so grateful if anyone could tell me how to sort this without having to get in a plumber