Clean hands doctrine is used in U.S. patent law to deny appropriate legal protection to a patent holder who has committed inappropriate behavior, such as using the patent to extend the monopoly beyond patent claims.  This clean-hands doctrine can be used offensively by the plaintiff to claim another fair remedy, one imposed by law. Good faith (bona fides in Latin) describes the sincerity of a party in a trial. Sometimes that party has broken the law, but not intentionally, and the judge can take that into account. This is the kind of case where the judge may decide to settle the dispute in the courts rather than in the law. The judge decides to move away from the strict application of a text because the result would be unfair. It can even lead to a decision against the legem if it is necessary to party in good faith. The impure hands of a defendant may also be relied upon and proven by the applicant, in order to claim other appropriate remedies and to prevent that defendant from making an appropriate positive defence. In other words, “unclean hands” can be used by the complainant offensively and defensively by the defendant. Historically, the teaching of impure hands can be traced back to the fourth latranrate. [Citation required] Inappropriate conduct, prohibited by the clean hand doctrine, must be part of the transaction that is the subject of the dispute, it must not necessarily have directly prejudiced the other party. This is the great uncertainty when one party claims the doctrine of dirty hands, sometimes it will be impossible to prove that the other party knew that the application of the law was unfair and caused prejudice to the other party, even if it seems obvious, since it is not a written rule.
Misconduct alone cannot establish dirty hands and cannot be the basis for a conviction or release of the judge. In the doctrine of clean hands, it is said: “He who comes to justice must come with clean hands.” This general statement of principle prevents anyone guilty of misconduct in litigation from obtaining a discharge. It requires that the person who aspires to just relief ensure that his or her current balance sheet is clean in a transaction or interaction. The argument that one party to the dispute has “unsuitable hands” often appears in contractual disputes in which both parties to an agreement acted in bad faith, but one party wants the court to order the other party to do something (or stop doing something). Fraud is not necessarily illegal, it is unethical to say the least and should be punished on the basis of justice. That is why this idea is linked to that of good faith. The defendant is responsible for the proof and must prove that the plaintiff is rushing to the law to do something that the spirit of the text must prohibit. Therefore, the clean hands doctrine is a defence that can be made against the complainant who has committed fraud. It can neutralize a requirement that would end in something morally reprehensible or unjust. It punishes the inappropriate behaviour of the applicant, who should not receive what is required if the judge follows the letter of the law. Clean hands, sometimes such as the doctrine of clean hands, the doctrine of impure hands or the doctrine of dirty hands, is a just defence in which the defendant argues that the plaintiff is not entitled to obtain a just remedy because the plaintiff acted unethically or acted with bad intent with respect to the subject matter of the complaint. , i.e.
with “unclean hands.”  The defendant bears the burden of proof to prove that the plaintiff is not acting in good faith. The doctrine is often referred to as “those who seek equity, must make equity” or “equity must come with their own hands.” This is a matter of protocol, characterized by A. P. Herbert in the unusual law by his fictitious judge to say Mildev (as Herbert says “less elegant”), “A dirty dog will not have justice by the court.”  International law is a very specific area of justice in which each legislation is an agreement between two or more states.