

Look for military surplus stores. Military surplus stores are hit or miss on availability and quality, since they buy in bulk containers. Check over the piece of clothing thoroughly for damage.
You can also buy some of coats brand new from manufacturers like London Fog. They make an English officers coat that is lovely
Additionally gasoline degrades after some time and would be mostly useless after 4-5 years without substantial additives and work to bring it back into shape.
I believe kerosine can last up to 10yrs