Peggle 2 - Coolest Clear Achievement Guide
199A Cool Clear Style Shot is performed when you clear the last orange peg in a level and then hit all remaining pegs to clear the level.
The easiest way to do this is by leaving 1 orange peg, and 1 blue/purple peg very close to each other to finish the level. Now, bank off the orange peg, then hit the blue peg, and you will get a "Cool Clear", finish the level and get the achievement.
This can be done on any level, but I recommend doing this on Peggle Institute - Level 7, using Bjorn. Start off by clearing out the two circles, and the bottom semi-circle. Ideally, leave the green pegs untouched for until the final few shots. Clear out a good amount of the pegs, and then hit the green pegs to have some Power shots available. Now, make sure to clear all but 1 orange peg and 1 blue/purple peg on the screen, and make sure that you have the angle to hit both in one shot. Now bank the your shot from the final orange peg, into the final non-orange peg and you will unlock this achievement as seen in the video.
Note: This can be done on any level, and the video also includes Peggle Institute - Level 1, although there will be no power pegs, so it can be a little harder.