Vacuum the love seat to remove debris and dust. Use the soft brush attachment to avoid scratching the leather. If you have a strong vacuum, use a hand-held unit with less suction instead.
Combine a few drops of liquid soap in a bucket with a quart of distilled water. Mix the two together until it's sudsy. Dip a corner of the rag in the solution and test it on a hidden section of the love seat. Once you know it will not ruin the leather. dip the rag in and wring it out. Wipe the rag over the leather surfaces to clean them.
Dunk another rag in clean distilled water. Wring it out and wipe away soap residue. Dry the love seat with a dry rag. Use a buffing motion to restore the leather's shine.
Treat the surface with leather protector/conditioner as per product instructions.
Use a leather cleaner to remove grime and stubborn stains. It is specially formulated to be used in this manner and will be gentle on the leather.
Hold a rag over the top of the leather cleaner bottle and tilt it until there is about a tablespoon on the towel. Rub it over a small section of the love seat, using circular motions. Let it absorb for one minute. Wipe it off with a clean towel. Repeat if necessary.
Wash leather love seats with saddle or castile soap and water. Use more of the soap than water, working it in until the surface is clean. Wipe off soap traces. Dry with a cloth and polish with another soft cloth.
Moisturize dry leather furniture with a conditioner or leather dressing. Apply a small amount of the cream to your fingertips and rub it in until absorbed. Wipe off excess, and stay off the love seat for two hours.