Saddle soap to strip out oils - I've used the RW conditioner which darkened, but wasn't too bad. What killed any color in my boots was the RW store who used straight
Saddle and Tack Conditioner – Preservation Solutions
Saddle oil | Hermès USA
Saddle Soap vs Mink Oil: What Should You Put On Your Boots? - stridewise.com
What is the Best Oil for Leather? Neatsfoot, Coconut, Mink | Carl Friedrik
Short Term Conditioner Test #3—cracking prevention. Bick #4, Esquire, Lexol, Neatsfoot, Obenauf's Oil and Saphir Renovateur. : r/goodyearwelt
HOW TO CLEAN, CONDITION, REFINISH & PROTECT YOUR SADDLE - YouTube