Normally, deities 'altars cannot be moved, but now they are thoroughly cleaned, and a year's worth of incense ash is removed from the incense burners.
平日不能亂動的神案，趁此做一番徹底的清理，包括香爐裡積了一年的香灰，俗稱「清塵」，也就是清理灰塵的意思。