I would use Fractal Noise to create the steam. Put a feathered mask on the layer to make the shape you want. Tweaking the parameters should get you some nice smoky looks.
Then, I would use an adjustment layer to change the levels of the shot (to lower the contrast and add some blur it to make it look like the steam on the glass. Then I would use another layer as a track matte to wipe it away.
Szalam, thank you for sharing ideas! I try this, i understand.
Then I would use another layer as a track matte to wipe it away. = But how animate this wipe? With function Track Matte Key?
Im sorry, im newbie in this
If you're new to AE, starting with making effects like this is not ideal. AE is too complicated. You will get lost quickly.
I highly recommend getting a solid foundation in HOW to work with AE first before you start. Getting started with After Effects is a great, free resource!
But how animate this wipe? With function Track Matte Key?
You could do any of several things, you could use a shape layer with trim paths, animating a shape layer or a mask path, particle effects, text animators...
A track matte is a pretty useful function. After Effects Help | Alpha channels, masks, and mattes