Hi Sandy Do you mean Caulking, as in silicone or latex caulk?
If so, your best bet is to use a very sharp chisel and scrape with the flat (unbeveled) side down, slide it across the tub or floor and under the caulk. Should lift the caulk up without scratching the floor or tub. Do this in long and slow strokes...don't do short choppy strokes. Laquer thinner or acetone should clean up any residual amount (make sure to ventillate the area well), then scrub the area with a good floor or tile cleaner and let dry before appling new caulk.