A great exercise to practice the bounce in the bottom of the front squat. In the snatch it is, as a solid rule of thumb, not necessary to get a bounce because the main obstacle is to get under the barbell, securing it over your head. In the clean however, and especially if you have a good pull phase and can move explosively under the barbell, your front squat strength will eventually be tested. It's much easier to do a heavy front squat with a controlled bounce from the bottom instead of either sitting completely still or letting the barbell crash on you and ruin your posture. In order, then, to do the one-and-a-halfs from the bottom you'll have to be in good control of the barbell during all of the front squat phase. This has a nice cary over to a normal clean. Try it!
Oh yeah, and don't forget to re-grip at the top.