After the Wei Ya dinner, it is time to thank and send off the Kitchen God. This folk custom can be traced back to as early as the pre-Qin era (earlier than BCE 221). On the 23rd or 24th of the lunar calendar, the kitchen must be cleaned after evening. The ritual to thank and send off the Kitchen God to the Tian Gong (Heaven Palace) uses incense, candles and offerings such as candies, rice crackers, rice cakes which are placed in front of the Kitchen God. On the early morning of Chinese New Year Eve, the Kitchen God will be welcomed back again before preparing for the Chinese New Year Eve reunion dinner. The ritual to thank and send off the Kitchen God has evolved into a custom of sending off deities, and then welcoming them back on the 4th day of Chinese New Year.