I experimented with some diesel storage options, and one that worked out well is mylar water storage bags (in cardboard boxes)
DO NOT TRY THIS FOR GASOLINE! It wont work!
Step 1: Reinforce the Spout
I used a little hard-board to reinforce the spouts, not a necessary step but it helps when using the flex pipe as a spout .
I used some basic plumbing drain parts to make a cap. This took some fiddling to find a combination that was leak proof and air tight, but it is do-able.
The original silicone caps also work fine, but pouring the fuel out requires a funnel.
I used yellow duck-tape to close up the cardboard box- on my water boxes I use clear packing tape- but I wanted the fuel boxes to be a little stronger and easy to recognize.
Step 2: Flexible Drain Pipe As a Fuel Spout
This won't work with the smaller fuel inlets on cars, but it does work with truck size inlets.
In hindsight I think staying with the original silicone caps and using a large funnel is better, but if you want to experiment, this worked out pretty good.
Step 3: Add the Recomended Amount of Diesel Fuel Stabilizer
Fill with fuel and add some fuel stabilizer. I was sure to press all of the air out of the bags before capping it closed.
I left one box sitting outside in direct sunlight from April through October without stabilizer and it was still clean and ran fine.
I stored four of these (with stabilizer) inside a shed for a year and the fuel was still clean and ran fine. This might not be the most ideal storage method, but it does work. At less than $10 per unit (I paid $76 for 10), it's stack-able and tote-able.
The best thing to know is the Mylar bags will hold diesel, and as long as the bag is air-free the fuel is usable for at least 6 months, a year or more if you add stabilizer.