Rarely do you EVER need 5 gallons of sanitizers. The great thing about no- rinse/wet contact sanitizers, like Starsan and Iodophor, is that you really just need enough to slosh around. On a normal brew day I only mix a couple gallons or so.
If you use starsan and mix it with distilled water, you can re-use it for weeks, if not months. Even iodophor if mixed with distilled or pre-boiled water and kept sealed between uses, you can get a couple 3 days out of it, maybe even a week, if you add a few drops of fresh.
Because of this many of us, especially starsan users keep a spray bottle with starsan (and I've even done it with iodophor mixed a little stronger than normal) with distilled water. Just to spray things like that with.
I use a nice quart sized spray bottle with 2 ML of starsan in it. I use a children's medicine dropper on hand to mix the starsan with.
Also you can buy your distilled water in plastic gallons, spill a little out and add a little less that 1/4 of an ounce of starsan to each, and just keep it sealed, then use as needed and pour back in.