Well first of all you have the right idea - succulents are easy to propagate and yes, you can save the ones with no roots. You just need to pick succulents that still have some green left on the tip growth. You can pull away any of the dead leaves surrounding the green tip growth and cut the long stem off or dead roots off. Then just set the newly cut succulent tip on top of moist soil, using a bit of wire to hold it down if necessary so it makes contact with the soil. Do not overwater. Keep soil just barely moist. Misting the soil is usually the easiest way to do this. Place the new plants in bright light not full sun until they form roots. You can also start a new succulent plant from a single leaf. Just poke the stem  end of leaf into soil that is kept barely moist. Once new roots form on your plants you can transplant them into pots using soil made for cacti and sedums. They must have really good drainage and never stand in drainage water. I see lots of baby succulents in your future. Keep growing, Marianne Binetti