Net profit is the result of sales or income after deducting cost of goods sold, fees and taxes.
As an entrepreneur what you want is net profit, not just turnover, but from large turnover or sales it is hoped that you can get a large net profit as well. As for employees or workers, the income earned after deducting deductions, will get net income or take home pay (THP). So net means net profit and net income, it doesn't mean that it's clean and nothing left, right!
In the context of Muamalah Maliyah, clean can be interpreted meaningfully clean from things that are forbidden, which means coming from halal sources, halal ways, and halal processes.
Halal or not must be measured by fair standards, which are determined by the Most Just, through His Messenger, so that in obtaining income, the standards are the Al-Qur'an and Al-Hadith, which have been explained in the field of Muamalah Maliyah.
Fiqh Rules
Scholars have provided very light explanations, these explanations are compiled from various problems in fiqh because of similarities, so that ijtihad can be taken by Mujtahid, which are referred to as fiqh rules (fiqh), examples of fiqh rules in Muamalah Maliyah so that net profits are maintained are:
"The original law in business activities is permissible and permissible, unless there is a valid and sharih text prohibiting it.
"The benchmark (to determine the validity) of a contract is its purpose and meaning, not the words and its name."
"It is forbidden to acquire and use wealth in vanity"
"Do not do harm to yourself and do harm to others"
"Considering circumstances (which can be categorized as) Emergency and Hajat"
"Pay attention to customs and traditions that do not conflict with Shari'a"
Closing
Apart from knowing the rules of fiqh, of course you have to understand the fiqh, but there is another easier way to keep a clean profit, which is to ask the experts, just ask directly, so that you can focus on the profit, how do you know the net profit?, you can ask directly.
Wallahu a'lam bishawab.