1997crich

Hi there. I was recently given a 1927 set of proof coins, 1937 16 piece, 1950 and 1951 set. Unfortunately I promptly sold them all, except the 1937 set (which has both pennies missing). The process really sparked my admiration for coins, something I left behind somewhere between school and work. I have dug out my old coin collection and started going through it ( much to my wife's annoyance as she says I am now like a golf husband) I have come across a coin that could possibly be a proof but a very scruffy one. It is a 1932 South African silver sixpence with crowned George and a flower on the reverse. The coin is quite common unless it is a proof, of which only 40 or 50 were made( I think). Does anyone know how to tell if a very toned and/or dirty coin is actually a proof coin? I have a few other silver coins which I'm not sure about so any information would be great to help me sift through my coins.