[ap1188]

First of all, you can't repair cracks. If the saddle you bought is cracked, you'll never be able to oil that away. Eventually they'll spread, but you can do your best to keep them as small and minimal as possible.A good oil to use is the Lexol brand of oil. This is higher quality stuff and thus it's more expensive. I suggest first cleaning the saddle with a good glycerin soap, something basic and not too expensive. This should get out the dirt and grip. When it's dry and clean, oil it intensively with either the Lexol product or a deep oil or conditioner. You may have to do this several times (making sure to give the saddle plenty of time to dry and absorb the oil). This should return some of the suppleness to the leather.Make sure you also clean and oil your tack regularly. Especially with a used saddle, you need to be careful to keep it from deteriorating. Keep an eye on the cracks in the saddle. If you see them starting to spread, the saddle may be on it's last legs.