As Bish said, sometimes way overdone on some models. I use hairspray, salt and pencil methods depending on the application.
Hairspray from the dollar store does the same thing as those tiny expensive brand name chipping fluid bottles. Click on the pictures for closeups.
Hairspray method on my Tamiya Seiran exposing the Jap red primer used in Naval aircraft. I also used the pencil method for deeper paint damage
The salt method is good on heavily chipped late war Japanese aircraft giving true chip damage:
#2 pencil has darker lead and looks as older paint damage: