A Brooklyn teacher’s efforts to teach character to his students netted him a $4,000 fine for violating city ethics rules.

As part of a “Character Incentive Program” at P.S. 66 last year, teachers were instructed to award “character keys,” or stickers that students could redeem for prizes. Marlon Scantlebury, a 14-year teacher who works with middle schoolers, decided to award “keys” to students who bought soap that members of his family produced, according to a disposition released today by the city’s Conflict of Interests Board.

At least five students bought soap at $3-4 a bar, earning dozens of character points, according to the disposition. One student also got a pass to avoid one night’s homework when Scantlebury changed the reward for purchasing soap in January 2012.

The venture, which earned Scantlebury no more than $30, violated rules that prohibit city employees from conducting personal business while at work and from using their positions as public servants to profit financially, according to the Conflict of Interests Board.

Scantlebury accepted the ruling and agreed to pay a $4,000 fine for his behavior. He also received an official letter of reprimand in his personnel file, according to a Department of Education spokeswoman.

The conflict board’s press release and disposition is below.