Just be careful on aluminum:
Aluminum - Is it safe to use Simple Green on aluminum?
Simple Green products have been successfully and safely used on aircraft, automotive, industrial and consumer aluminum items for over 20 years. However, caution and common sense must be used: Aluminum is a soft metal that easily corrodes with unprotected exposure to water. The aqueous-base and alkalinity of Simple Green or Crystal Simple Green can accelerate the corrosion process. Therefore, contact times of All-Purpose Simple Green and Crystal Simple Green with unprotected or unpainted aluminum surfaces should be kept as brief as the job will allow - never for more than 10 minutes. Large cleaning jobs should be conducted in smaller-area stages to achieve lower contact time. Rinsing after cleaning should always be extremely thorough - paying special attention to flush out cracks and crevices to remove all Simple Green/Crystal Simple Green residues. Unfinished, uncoated or unpainted aluminum cleaned with Simple Green products should receive some sort of protectant after cleaning to prevent oxidation.
