Well, alcohol can harm some stock finishes even if it doesn't hurt metal or synthetic parts. I know the pain of intending to maintain a gun and unintentionally using something that turns out to hurt it or its looks.
Alcohol is hydroscopic (I hope that's the right word): it draws moisture from the atmosphere. You only want to use it in situations where you can dry the parts. But if you are using a spray cleaner, that usually means disassembly is not an option.
The two spray cleaners I have for guns, for which I have no clue on detailed disassembly like my aunt's .25 Colt pistol or gun parts like M1 carbine bolts which require tools for proper disassembly, are Rusty Duck Gun Action Cleaner and (last resort) an automotive brake cleaner. I have stuck to using them on blued or parkerized steel only, no synthetic frames or enamel finishes. Remove from the stocks and take on the deck on a windy day kinda cleaning. But sprays tend to strip lube and protection from the metal. Which means you have to find a way to lube and protect without gumming up the works.
I use a heirarchy of cleaning fluids based on degree of harshness needed. If I can wipe the parts dry, I'll use Windex first, then WD40, 3-in-one, isopropol alcohol. If I can't wipe the parts dry, I do not use water, alcohol or stuff like WD40 or 3-in-1. WD40 and 3-in-1 gum up over time because they try to be solvent, cleaner and protectant. Instead of spray with these cleaners, I prefer to use cleaning implements like toothbrush, q-tips, pipe cleaners, and bamboo skewers whittled to a pick point on one end and a wedge on the other.
On gun cleaning I usually use Hoppes Number Nine nitrosolvent (the used patches keep the gnats away from the trashcan). For some types of gunk, alcohol, lighter fluid or acetone are called for but they will damage some finishes. Removing old camo tape from a gun is never fun. After cleaning, protectants include a good gun oil or CLP or Mobil which are also lubricants.
