>We have in our collection leather bridles, halters, reins, saddles, >saddlebags and so forth that have a white "bloom," which I'm assuming is >mold. It wipes clean, and I've used basic saddle soap which also removes >the film. What you have is called spue (or spew, if you like). It looks like mold in texture but is actually a result of excessive moisture in the air reacting with a recent treatment of the leather. (Biological examination under microscopy will confirm this.) Saddle soap is no good for this kind of treatment, in fact, saddle soap can cause the problem. To clean spue, apply either denatured alcohol or mineral spirits. A better treatment would be Vulpex soap mixed with distilled watrer or mineral spirits. Back in September we had the same problem in our saddle collection. Our HVAC system had problems right at the time of some unusually heavy rains. We treated some saddles with the alcohol, and others with the mineral spirits. The results were almost identical. I like the alcohol because of its quick evaporative quality. It leaves no film nor residue. In the intervening 6 months we have had no reoccurrance of the problem. (The HVAC has been fixed, too.) After cleaning off the spue, continue to monitor the environment. In closed micro environments, silica gel will help control excessive moisture. If you determine mold present on leather, it can be treated thus: Dry the storage enviroment with silica gel or isolate the objects into a closed environment (poly bags) and use the silica gel inside the bag. Monitor each environment with an RH strip. After the mold dries, use a semi-stiff brush in good ventilation to brush off the mold. White hair bristle brushes with flat ends work best. These don't hurt the leather, but will pick up the mold. They're available from Light Impressions, or most art or library suppliers. It's a good idea to also use a mask, vinyl gloves, and eye protection. Treat the leather with ortho phenyl-phenol (OPP) to prevent spores from regenerating. Talus and Conservation Materials both carry OPP. An alternative is to swab the surface after brushing with denatured alcohol, which will also prevent spores from reoccurring. Continue to maintain a proper RH environment. The ideal humidity for leather is 50-55% with an internal moisture content of 12-15%. If ideal rh is maintained, the moisture content will be pretty much automatic. For more information on leather treatment, contact Paul Storch, Conservator at the Minnesota Historical Society. He's the best leather man in the business, and has often taken the time to give me free advice over the phone. He has also done work on contract for us. He's good. His phone is 612/297-5774 or you can reach him at his private lab at 612/729-4449. Good luck. HBC ***************************************** Henry B. Crawford Curator of History [log in to unmask] Museum of Texas Tech University 806/742-2442 Box 43191 FAX 742-1136 Lubbock, TX 79409-3191 *********All opinions expressed are mine**********