As said in the description, this brush will remain free for users/downloaders.
This cloud image can be used for steam, actual dust, smog, and many other things. The limit is the user's imagination.
Step one: Open Materials tab
Step two: Select Soft little Dust Cloud and place it where you require it to be
Step 3: Adjust using the usual right-click options.
NOTE: CS keeps deleting my brushes and images, even though I put more effort in than they think. So, I guess I'll keep uploading them until they stop. They will remain free BECAUSE I KNOW NOT EVERYONE CAN AFFORD THEIR PAID STUFF.