You can look at your charger to see which pins are marked + and Negative. Assuming Pin 1 is on the Left of the charger, + is pin 2 and - is on the farthest right- pin 3. The batter has slots for 6 pins. Pins 1 and 2 line up with the left most slots as you place the battery in the charger, pin 3 lines up with slots 6 of the battery.
I've "hot-wired" a charger for a Lithium Pack before- you must be very careful to not let it overheat. That left-most pin, pin 1, tells the Leica charger when to quit. The pack is 3.7v, meaning you should use slightly higher Voltage to charge- like 4.5v or so. I would buy two of those cell-phone back-up battery chargers that themselves charge off a USB port. Get two, cut up the cord on one to bring the power out to the Leica battery. The back-up battery pack will run out before damage can occur to the Leica battery.
First try a good squeeze type blower, the Giottos "Rocket" type have a filter for the air intake. I've used a standard type bulb blower, no brush. Open the shutter in "Sensor Clean Mode" and see if it will just bow off. If that does not work, I use the Eclipse wet-cleaner and wipes.
If you use older lenses, change lenses often- make sure the mount of the lens is clean. I cut way down on debris getting into the camera by making sure the threads of my older Thread Mount lenses are clean, and mount them on the M adapter before putting onto the camera.
I also recommend using some contact cleaner from time to time. DeOxIt is my particular favorite. It removes invisible debris and oxidation that can really mess with communication between lenses and bodies, and batteries and chargers. Use it sparingly though - a very small amount on a small tip (such as eye shadow applicators) goes a long way. For what it's worth, this has solved over 90% of my otherwise unexplainable camera behaviors.