I've seen somewhere where adding neat's foot oil and beeswax to your soap recipe makes a good saddle soap. Also tea tree oil to prevent mildew. Never made it myself and not sure of the percentages though.
Here's a recipe from Herb and Companion magazine:
Beeswax Saddle Soap
2 Tablespoons grated beeswax
1/2 cup olive oil
1 cup grated castile soap (I bet you can use most any soap.)
1/4 teaspoon lavender or tea-tree eo
Heat olive oil until warm and stir in grated beeswax until melted. Add grated soap and stir until melted. Stir in essential oil and pour into shallow lidded tin. Let cool.
To apply, scoop up a small amount of saddle soap and rub onto leather in a circular motion using a sponge or loofah. Rinse with a damp cotton cloth. Allow leather to dry completly before conditioning with Boot and Saddle Conditioner. (recipe follows)
Boot and Saddle Conditioner
Helps leather shed water while it adds a supple, polished look. Use 3 times a year. It's smell repels mice, raccoons, porcupines and little critters who love to chew on salty leather.
3/4 cup olive oil
3/8 cup castor
1/4 cup grated beeswax
1/4 cup carnauba wax
1/4 teaspoon lavender or tea-tree or eucalyptus essential oil
Melt all ingredients mixing well. Pour into shallow tin. Let cool. Rub into leather with a soft cloth. Let dry and polish gently."
