Hi - In June 2014, I purchased a mobile home that was built in 2001. It has a MARCO Direct Vent BDM35 gas (propane) fireplace. Maintenance was kept up. But I have what appears to be rust or discoloration in the fireplace. wondering if this will create a problem when using this winter (not sole source of heat)? Wondering if there is something I can do -- possible paint with fire rated paint? to make this go away. Was quoted in excess of $6,000 to replace this thing ... one of the main reasons I bought the house .... need to make it safe -- Suggestions and thoughts please before I turn it on? PHOTO -- click on to open, but pay no attention to that white space at the top -- it is NOT a part of the fireplace --- shot the photo through the glass, it is a reflection of something behind me.... thanks,