You don't have to be a teacher to make money out of knowledge.

Some high school graduates used their brains to earn some cash after they got admission in prestigious universities recently, reported xkb.com.cn on Friday.

They started selling their notebooks where they had written all the key points of their lessons of three years or more.

According to reports, some graduates in Dongguan, Guangdong province, who were admitted by Fudan University, one of China's top universities, opened an online shop to sell second-hand notebooks of theirs.

To promote their "products", one of the sellers created a public account to teach people how to take notes both practically and aesthetically and won more followers.

The notebooks they were selling showed exquisite layout, good logic and classification.

This happened not just in Dongguan. Top graduates in Guangzhou decided to cash in on notebooks, too. They worked together to assemble and re-organize the notebooks of different subjects into different series.

Afterwards, they took orders from grade one to three and then printed the notebooks in bulk to sell.

"The reason we jointed together is because we have different teachers and they may have different approaches to analyze the problems. That might help," said one of the students who launched the event.

These notebooks selling from 9 yuan ($1.35) to 39 yuan per copy, include notes, research and exercises in both handwriting and print versions.

According to one of the students who launched the event, they made more than 10,000 yuan in profit.

But there are some who think differently.

He Yulin, whose college entrance exam score was among the top 10 in Guangdong province, has an emotional attachment to the notes.

"I want to keep them as they are the result of my hard work and memories, although many students came to ask for them," said He.

And it's not just notebooks that are turning out to be money-making machines. Tuition is another are where students are earning big.

Li Jiong, a graduate who scored high in the college exam, made a plan for herself to make the first pot of the gold on her own.

She created an advertisement with her introduction and posted it on her WeChat, one of China's most popular social networks, saying she can tutor students in Math, Physics, Chemistry and Biology.

She set a price of 120 yuan per hour for one-on-one teaching and 90 yuan per hour for group sessions.

In just three days, she received orders from over 10 people. According to Li, she had a full schedule from July 10 to 20.

"I can tutor four students a day with average income of 600 yuan. I'm planning to tutor until the end of the month, then I can have over 10,000 yuan in 20 days," Li said.

Li said she valued her first batch of clients as they may want her help next year.

"I just passed the exam when I know all the key points of the subjects the best. I want to make the most of it to become independent financially."