A callus is a thickening of the skin that occurs in response to repeated friction, in order to protect the area that is affected. If you remove the calluses, then you will need to either wear gloves or other protective gear to prevent them from reforming.
Once you have calluses, there are a few ways you can reduce them. It's not recommended to simply cut them off or similar, as the skin underneath will (generally) not be sufficient to protect the area when the stress reoccurs. This can lead to blisters and/or breaks in the skin, which opens up the possibility of infections.
Lotions and soaks such as epsom salts can help soften the area, and then something like a pumice stone can be gently used to abrade away the surface of the callus. Again, do not try to remove the entire area at one time. There are also many home remedies such as soaking in chamomile tea and similar, but I have no experience with their efficacy.
If you wish to prevent them in the future, take note of where on your hands they form, and then look for gloves that have padding in those specific areas. Be aware, that even with good gloves, you may still get callus formation.