Cosmic Carbone or Cosmic Elite? For Elite, just sell them and buy Ellipse, they are basically the same rims. For Cosmic Carbone, an Allen key skewer or tapping the axle and fitting bolts will do up front, but the rear is probably not worth the effort; you'd have trouble finding a track hub to line up with the lacing pattern, which needs to be fairly accurately replicated as the spokes pass through the carbon fairing to the aluminium rim, and converting the FTS-L freehub to fixed is just about feasible but more expensive than just buying a proper track wheel.
Cosmic Carbone or Cosmic Elite? For Elite, just sell them and buy Ellipse, they are basically the same rims. For Cosmic Carbone, an Allen key skewer or tapping the axle and fitting bolts will do up front, but the rear is probably not worth the effort; you'd have trouble finding a track hub to line up with the lacing pattern, which needs to be fairly accurately replicated as the spokes pass through the carbon fairing to the aluminium rim, and converting the FTS-L freehub to fixed is just about feasible but more expensive than just buying a proper track wheel.