Great white sharks. Trophic Pyramid Information that is in video: An ecological pyramid (also trophic pyramid, energy pyramid, or sometimes food pyramid) is a graphical representation designed to show the biomass or biomass productivity at each trophic level in a given ecosystem.
The risk is that you may not be able to remove all the acid and if it is left on the metal it will continue to corrode the metal. So to give you a quick answer, you can use vinegar to etch the aluminum, but you have to rinse the surface thoroughly to remove all the acid residue.
Balsamic vinegar, for example, is made from must (unfermented juice). Just naming the most common types of vinegar gets you a sizable list: red wine vinegar, apple cider vinegar, malt vinegar, balsamic vinegar, rice vinegar--and you've barely scratched the surface! Would you believe coconut vinegar, raspberry vinegar, honey vinegar and even beer vinegar (must be over 21)?