The money man

hi i have a number of old pennies that would have been very nice coins if it wasnt for this surface rust? is there any way of removing it without wrecking the coin any more than it already is ?

Thanks gx do you know if there was a commemorative reason behind it?

That is it gx do you know what they might be worth and if they are rare and any info you might know about it I can't find much about it myself Thanks in advance

Hi just after some info and a value of a 1970 royal Australian mint Canberra medallion in the case in mint condition. It is quite large and has all the Australian coins in circulation on one side and a building with canberra written on it on the other. I think it is made of bronze ? Please any info would be appreciated thanks in advance