Solutions that come in concentrated form requires dilution. Before applying the solution to the dirty surface, you must first mix it with some parts of the water. If the contamination on the coils is severe, then a concentrated solution can be used to clean and brighten the aluminum surface.
Solutions that come in an aerosol can don’t need to be diluted. They can directly be applied to the surface. If you are looking for a detergent that you can use quickly, then aerosol-based detergents will be ideal for you.