Unless the room temperature drops below 70 degrees Fahrenheiht or 21 Celsius then you do not need to keep the heat lamp on at night. In fact, it is healthier for your dragon to cool down to a safe lower temperature than he is during the day. Letting the enclosure temperature drop at night will help prevent your dragon from getting dehydrated as well as helps your dragon to get a better rest. If the room temperature of the room your dragon is in drops below 70 degrees F or 21 Celsius at night then you should keep a heat lamp on at night that does not let off any light.
Your heat lamp should be placed to one side of the enclosure to help create a warm side of the enclosure and leave the other side cooler so that your dragon can regulate his temperature externally. Your UVB shoud ideally be a long tube bulb that can span most of them length of the enclosure, if it does not then place it where your dragon spends most of his time regularily. It it very important that your dragon is exposed to UVB lighting during the day.
Water and vinegar can be used to clean your dragon's enclosure. Here at KBD we often use Dexidin 4 detergent dilluted in water to clean our enclosures with. There are also many cleaners that can be bought at pet stores that you can use to clean your Dragon's enclosure with. Please be sure to always rinse/ wipe down your enclosure with just water after using a cleaner to insure that no cleaner residue if left in the enclosure when you put your dragon back.