Dirt stuck on bodywork + corrosion on metal parts

[dartmouth100]

Hi all, I have been recently restoring this older Vespa 50 s scoot, and I have noticed that there are some visible spots of dirt on the bike which are difficult to get off, I run my fingernail over them and they will not go away. What is the answer to this ? Photos of this problem are attached. There seems to be this ingrained dirt all over the bike. Although it's not too visible - I know it's there and it is bothering me.

Secondly - especially around the grab bars and the mirrors it appears the metal is corroded slightly. Is there a way of removing this corrosion ? Once again photos are too show

The previous owner had some nasty incident where one side of the grab bar has some deep scratches - can these easily be removed and if so how ?

Thanks once again guys I know you all probably thing - ohh heck ahah but I am very new to all this