Rubberised paint which the containers come painted in suits the requirements for a lot of people. Sometimes your local licensing officer will demand wood lining though.
If you want any advice on storage I'm happy to help. Are you looking to store CAT3 or CAT4?
david here from Brothers pyrotechnics. I will help you in any way I can. Call me and one of our reps will get some stuff out to you/ come and see you to give you all the advice you would need. 0785 3213895