I started in this hobby in the 1960's when all we had were the metal cans. Cans will rust, you can't see any junk in the fuel and, in my opinion, the fuel gets hotter when sitting in the sun. Sunlight will NOT affect the quality of fuel in a sealed transparent plastic jug.

My problem is one formula of fuel won't meet my diversified flying needs. I fly control line with both old, plain bearing, iron piston/steel sleeve metallurgy which needs fuel with a high castor content (28-29%). I also fly modern plain bearing, ABC or ABN schnuerle engines which need a medium castor/synthetic blend (20-22%). I also have modern ball bearing ABC and ABN engines which can use off-the-shelf commercial fuel blends with 17-18% mostly synthetic oil content. I just recently picked up a ball bearing ringed 4 stroke engine which has it's own unique requirements. And finally, I have a handful of ½A engines which typically require a higher nitro content than my sport fuels for larger engines.

My solution is to buy empty half gallon or quart plastic containers and custom mix the blends I need to meet my needs. One of my control line club members worked at a car dealership. He'd collect the empty 1 quart containers from windshield washer solvent which were triangular instead of round. These were great for our model needs.

There was some publicity regarding a well-known commercial fuel supplier whose plastic containers developed leaks. People who bought a case of fuel (4 gallons) and stored it in their garages only to find a good portion of it had leaked out by the following spring. The problem was traced to a faulty supplier rather than an overall design deficiency of plastic containers in general.

The only type of model fuel which REQUIRES a metal container would be diesel engines. The ether used in model diesel fuel will evaporate through the walls of plastic jugs.