Why not just read up on the manufacturer's data sheet, which specifically lists the NSF/ANSI rating for each different colored brute trash can? If you decide to use it despite those ratings then that's your choice.
My job is in plastics so i'd like to think i've picked up a thing or two over the years. These brute trash cans are predominantly made from HDPE. If you buy them brand new they are completely safe for aquarium use, colour has no bearing on this at all. I think tlindseys post regarding his 20 years trouble free experience says it all really.
In the hobby we regularly come across several types of plastics. PMMA, PVC, ABS, PET, HDPE and PP are the main ones. They are ALL completely safe BOUGHT NEW. Problems tend to arise when hobbyists start using USED plastic tubs, buckets, barrels, pipework, tubing or whatever. Most plastics absorb (very very low quantities though) of liquid they come into contact with. Hence the common phrase "leaching". So a previous substance, no matter how well you clean the plastic, can release itself into your tank water over a period of time. Now if you're talking toxic chemicals for instance then that would spell disaster.
So basically as long as you buy brand new you can sleep easy at night. If you go down the USED route find out what was in contact with the plastic previously, if possible. Sometimes you can get away with just washing an old plastic tub in hot water to render it safe. Other times, if it contained chemicals for instance, then you'd be safer to give it a miss.
The people on here that use rubbermaid trashcans for storing water, are their any things I should know before getting one to hold water for water changes?
I’m planning to just get a 55 gallon and move it around for when I need to fill different tanks.