Hello We have a fairly new Heat & Glo SL-550TRS-D DV w/IPI Zero Clearance Propane Fireplace. Fireplace http://www.grillandhearth.com/details/Fireplaces/Direct_Vent/Heat-N-Glo/6094940070.html However when I put new D-Cells in the battery holder, the fireplace would not start! The first year I had the fireplace, I left the batteries in too long and there was a little leakage. However it cleaned up pretty well So I got out the Battery tester and tested the batteries. Yes there were good! Then I got out the Volt-Ohm meter and tested the voltage between the plus and minus of the battery holder wires where I disconnected them from the fireplace! Ah Ha very little voltage not 3 Volts like it should be. The scale was on 5 volt DC scale so it was easy to see how little voltage was there. Then I put one battery in and tested half the clip. Ok 1.5 volts. Put the battery on the other side and ah ha very little voltage!. So I soon realized that the top of that battery was not making contact with the battery holder contact. The contact did look like there was some oxidation and corrosion! Luckily when I sent away for the Harbor Freight Bottle Brush kit I also got the piece brush kit Where to buy Bottle type brushes for cleaning squirell cage blowers and chambers in wood pellet stoves? https://www.hearth.com/econtent/index.php/forums/viewthread/81280/ Also got the 6 piece brush kit for $2.99 !! http://www.harborfreight.com/6-piece-detail-brush-set-93610.html This brush kit contains 3 types of brushes. 1. nylon bristles for tile 2. brass bristles for heavy duty dirt, paint and scale 3. steel bristles for really tough jobs << The brush I used to clean the battery holder contact! So I pulled out the Steel Bristle brush and cleaned all the corrosion and oxidation off that one contact. Put the batteries in and the holder back in the fireplace and it worked!! Nice Clean LP Gas Heat during a power outage - What more can you ask for? Click pics below to Enlarge!