If you own leather furniture, you've already made an investment worthy of years of enjoyment, so don't let water damage decrease the look or usability of your leather chairs or sofa. Contrary to what some people think, leather is not waterproof, and although it does have a sturdy composition, water rings and cracking can occur in fabric that has not been properly treated. Damage comes not just from the water, but from the chemicals and contaminants that are contained in the water, so it's important to prepare for unexpected flooding as well as periodic spills that can add up over time.
Remove excess debris. Before you apply any sealant, use a vacuum to remove excess dust and dirt. Make sure the suction is not too strong, or it will leave marks on the furniture. You also should use a soft brush attachment. Add a few drops of mild liquid soap to one quart of water and mix until you get suds. Dip a clean cloth in the soapy water and gently wipe off the furniture in sections. Using a second damp rag dipped only in water, wipe away the soapy residue. Use a third rag to dry.
Test for color fastness. After checking the furniture manufacturer's tag for sealing recommendations, take a small amount of the sealant and apply it to an area of the furniture that will not be seen; the back corners of a sofa cushion are a good place. Make sure you use a cloth that will show contrasting colors, and also use enough sealant to wet the area. Do not use the product if the color comes off.
Apply your sealant. Sealants should be applied in a well-ventilated area. If you're using a spray-on sealant, make sure the surface is completely dry and spray liberally over each section, but do not saturate. Let dry, then apply another coat. For cream or liquid sealants, apply in a circular motion with a towel or sheepskin and let sit overnight. Buff to a finish with a towel.