I recently acquired a second-hand bike and decided to repair it: The chain and the freewheel cogs are in very poor condition and rusty as you can see in the pictures below:
The bike has not been used for a year by the former owner. As I don't have that much knowledge about it;
I was wondering: Should I change the chain or repair it? as for the freewheel, can I even repair it?
If I have to repair them how can I achieve it?