Lambchop - you can buy cheap used vegetable oil containers- ( Speaking French helps!)
As long as you don't need them to last a long time, then they are fine -wash them out with a bit of fuel and that's sorted- colour- anyone you like as long as it is green or yellow! but mostly green. If one thing excels in Africa, it's the huge variety of Bidons! Personally, I'd seek them out in the main market, 10 mins walk from the Hotel Halima in NCK
When you no longer need them, give them away- loads of kids etc will take them off your hands and be glad to have them.