TL;DR: Year-end altar cleaning (bao sái bàn thờ) is commonly performed on the 23rd day of the 12th lunar month, the day of the ông Công ông Táo (Kitchen God) ritual, or on the 25th or 27th, as long as it is finished before New Year's Eve. The cleaning follows a set order: ask permission, wipe Buddha statues first, then ancestor tablets, then the incense bowl, and finally put the altar items back. Folk custom avoids moving the incense bowl, pulling incense sticks at noon or in the evening, and letting outsiders touch the altar.
What is year-end altar cleaning and why must it be done before New Year's Eve?
Bao sái bàn thờ is the year-end cleaning and rearranging of the worship space, including wiping the incense bowl, tablets, and statues, trimming incense sticks, and changing water, rice, and salt. In Vietnamese culture, the altar is the most sacred and revered place, where ancestors reside, so keeping it clean shows the descendants' care and respect[1]. Researcher Ngô Hương Giang defines bao sái of the incense bowl as the ritual of tidying the altar, trimming incense sticks, wiping the worship objects and rearranging the altar table[2].
The cleaning must be completed before New Year's Eve[1]. The reason is that after the New Year's Eve transition, the worship space is considered settled to welcome ancestors back, so the incense bowl and tablets are no longer touched.
When should year-end altar cleaning be done?
The most common day is the 23rd of the 12th lunar month, the day of the ông Công ông Táo (Kitchen God) ritual[1]. Families may also choose the 25th or the 27th if the 23rd is busy, as long as it is finished before New Year's Eve[1].
Researcher Phạm Đình Hải holds that before the ông Công ông Táo offering the family should only tidy and arrange the altar neatly; the full cleaning comes after the offering, and the trimmed sticks and incense ash are burned after the votive paper is burned[3].
On ordinary days, household members can clean the altar whenever it is dirty, but during Tết this is done more thoroughly and is called bao sái[1]. Extended family heads or eldest sons have many other rituals to handle, so timing can be flexible[1].
The table below summarizes the usual time frames chosen during Tết:
| Time frame | Meaning | Note |
|---|---|---|
| 23rd of the 12th lunar month | Day of the ông Công ông Táo ritual, a good day for cleaning and trimming incense sticks[1] | Most common |
| 25th of the 12th lunar month | Good day for trimming incense sticks, creating a clean worship space[1] | Suitable for families busy on the 23rd |
| 27th of the 12th lunar month | Good day for the incense-trimming ritual[1] | Must finish before New Year's Eve |
| After the 23rd | Still acceptable, as long as before New Year's Eve[1] | Avoid leaving it too late |
Who should clean the altar?
According to folk belief, the best person to clean the altar is a household member, usually the head of the family, someone who is not injured, and a woman who is not menstruating[1]. The person should bathe and clean themselves before cleaning[1].
In particular, when cleaning the altar for Tết, do not ask outsiders for help[1]. This belief stems from the altar being the family's private space, which only household members understand how to arrange and have responsibility toward the ancestors.
What are the steps in cleaning the altar?
The usual order has five steps: prepare items, light incense to ask permission, clean, trim incense sticks, put items back[1].
Step 1: Prepare cleaning items
The family should prepare red cloth or red paper to place items on while cleaning, avoiding wiping objects directly on the altar[1]. Use a new, separate broom or cloth[1]. First wipe with clean, warm water; then use white alcohol with ginger or ngũ vị hương water to clean[1].
Step 2: Light incense to ask permission
Before cleaning, prepare a plate of fruit to place on the altar and light incense to inform and ask the deities and ancestors for permission to clean the altar and the feng shui objects in the house[1].
Step 3: Clean
You may move vases, water cups, incense burners, and lamps, but the incense bowl and tablets must stay fixed[1]. Wipe tablets with a mixture of alcohol and ginger or warm water, never cold water[1]. If the altar has both Buddha and saint tablets and ancestor tablets, wipe the Buddha tablet first, then pour out the old water and replace it with new water before wiping the ancestor tablets[1]. Wipe the incense bowl and candles with a damp cloth to avoid breakage, then gently wipe again with a dry cloth[1].
Step 4: Trim incense sticks
Hold the incense bowl with one hand, and with the other gently pull out each incense stick from the outside inward, counterclockwise[1]. Trim until only an odd number remains in the bowl, ideally 3, 5, 7, or 9[1]. Tiền Phong gives another rule: leave 5 sticks in the Earth God's bowl, and 3 in the bowls of the ancestors and the bà tổ cô[2]. Place the trimmed sticks separately on newspaper or clean paper and burn them when the cleaning is complete[1]. If the bowl has too much ash, use a clean spoon to scoop some out[1].
Step 5: Put items back
After cleaning, the head of the family puts the worship items back, replaces the cold water, replaces the rice and salt jars if present, and says prayers to invite the deities and ancestors back[1].
What folk taboos apply when cleaning the altar?
Folk custom avoids moving the incense bowl, tablets, or statues during cleaning[1]. The incense bowl is considered a place where consciousness gathers and connects the earthly realm with the underworld; moving it is said to affect this connection[1].
Also according to folk belief, do not trim incense sticks at inauspicious hours such as noon (12 o'clock) or in the evening, as this may affect feng shui and the family's psychology[1]. Trimming should be done when the family member is calm and respectful to avoid bringing bad energy into the worship space[1]. Do not clean the altar or trim incense sticks when feeling uneasy[1].
If the incense bowl or worship items need replacing, the family should perform a hạ giải (dismantling) ritual before replacing them[1].
Why wipe Buddha statues before ancestor tablets?
Wiping the Buddha first and the ancestors after is usually explained by the hierarchy of the worship space: Buddhas and saints rank above ancestors. Changing the water between the two wipings follows the same idea, so that the ancestor tablets are wiped with fresh water.
How does daily cleaning differ from year-end cleaning?
Daily cleaning is just wiping when the altar is dirty, while year-end cleaning is a more complete ritual tied to Tết and usually includes trimming incense sticks, changing water, and changing rice and salt[1]. Because of its ritual nature, the steps of asking permission and saying prayers are emphasized more.
