What is the ruling on seasonal work in a sweets factory for the Prophet's Birthday (Mawlid al-Nabawi), and what is the ruling on the money earned from it if it is impermissible?

Celebrating the Prophet's Birthday (Mawlid) is an innovation (bid'ah). The customs associated with it, such as making and selling specific types of sweets that are produced only for this occasion, share the same ruling as the celebration itself, as they constitute aiding in a forbidden celebration. Foods prepared on this day with the intention of rejoicing in the Prophet's Birthday are also an innovation. However, the money earned from these sales is not unlawful for the one who acquires it.