Is the repentance and remorse of Satan worshippers and of those expelled from Allah's mercy accepted? And what should the repentant person do to erase his sins?

Allah Almighty accepts the repentance of a disbeliever, no matter how great their disbelief, so how much more readily will He accept the repentance of a Muslim whom Satan has led astray? The Holy Qur’an clarifies that Allah forgives disbelievers for what has passed if they desist from their disbelief, and Islam nullifies what came before it. Just as Satan swore to mislead humanity, Allah swore to forgive them as long as they seek His forgiveness. The Qur’an and Sunnah (definition) urge against despairing of Allah's mercy, for He forgives all sins. The penitent should strive to increase in good deeds, such as prayer, honoring parents, jihad, and consistently performing righteous deeds, even if they are few. Among the means that aid in steadfastness in repentance are: supplication (dua), seeking sacred knowledge, and keeping good company.