1stC Roman silver coin sent for the ID- in the 'cooker' to remove crust - As dug and 'cooked' pictures
As you have probably figured by the unmistakable bowling-ball shape of his head, this is Trajan - Hadrian's immediate predecessor, 98-117 AD. I believe the obverse legend reads IMP TRAIANO AVG GER DAC P M TR P COS VI P P - a bit more cleaning will reveal whether I've got that correct or not - there are several minor differences possible in the obverse legend which would affect the date by a few years. The reverse is less of an issue - that's definitely S P Q R OPTIMO PRINCIPI, it shows Mars striding right holding a transverse spear and carrying a trophy over his shoulder. If I have the obverse legend correct, this coin dates to around 113-14 AD. RIC 270, RSC 372.
As a kid i was into collecting stamps and coins but this website of actually finding treasures buried in the english soil is amazing.