Oxidised radiator pipes

Hi, a novice looking for advice here... Cleaning up the flat we just bought and saw the pipes on the radiator here has oxidised. I scrubbed it up but some of the green has remained so I wanted to ask a couple of questions

A) how dire is it? B) is this something we could feasibly attempt ourselves or is it not worth the safety risk? B) what can we expect to pay for this kind of job? Happy with a ball park figure...