If I find out part of my income is Haram but I am uncertain about the amount or whether any of it remains unspent, what steps can I take? Will the income be considered Halal since I was unaware it was earned through Haram means?
If you find out that any part of your income is unlawful (Haraam), you must give it back either to the real owners of it, and if you can’t reach to the real owners, then to the Muslim authority ( Haakim al-Share who is the Marja; of Taqleed) to give it to the poor as Majhool al-Malik (unknown owner fund).
Your late knowledge about the Haraam does not release you from your responsibility to give it back totally including what you spent from it.
Wassalam.