You also don-t want to knock over the container, so a stable, rubber bucket makes a good choice. You will also need to be certain that the part you want to color will fit in the container without sticking out of the solution, and without touching the negative ground in the bottom of the container. Any acid that you don't use, keep in what it came in, or an old plastic bottle, like a bleach bottle. You can also store your used solution this way for doing more parts later. Acid and bleach make chlorine gas.
Safety also applies to the nitric acid, but in a different way.
It is imperative that you label and keep track of this stuff, as it is a stronger acid than sulfuric, and more dangerous. The last note about the acids is to mix properly when adding acid and water. Always pour acid into water, never the other way, and do so slowly, being sure to mix in well. There is a reaction taking place and it releases a lot of energy. During the anodizing process, you will be running electricity through a weak acid solution.