When you have located a target and then pinpointed it with the search coil, the last thing you want to do is damage the find by digging and hitting it with your spade or trowel.
Its best to start digging about 6 inches away from the target and dig towards the spot of maximum signal strength.
Some detectorists use electronic probes – these are hand held detectors which are useful when searching – they enable you to locate a find within a hole without unnecessary digging.
For grassland its worth investing in a sharp knife to remove a plug of soil around a signal (but be aware of the law concerning offensive weapons!)
If your signal disappears when you dig, check that the find has not slipped back into the hole – or that it is not stuck on the back of your spade. Anomalous signals can be caused by pieces of coke or loose cabling on your detector.
You should always fill the holes in afterwards – many landowners make this a condition when giving permission to detectorists to search their land. Unfilled holes can be dangerous to livestock – always make a point of leaving the site in the condition you found it.