He works in a laboratory specialized in pork

Q 1: I was working in a laboratory specialized in pork for six months. When the money I got from this job reached the Nisab (the minimum amount on which Zakah is due) and a Hawl (one lunar year calculated from the time a property reaches the minimum amount upon which Zakah is due) passed on it, I paid the due Zakah (obligatory charity). I worked in another laboratory and I mixed the lawful money I received from this job with that I earned from the other one. I now pay Zakah on the whole sum. (Part No. 11; Page No. 166) When I was working in the first laboratory, I was astray as I did not perform Salah (Prayer) or observe Sawm (Fast), then I repented to Allah (Glorified and Exalted be He).What is the ruling on this mixed money? Should I pay Zakah on all of the money? I do not know the exact sum of money which I earned from the first job and this is why I pay Zakah on all of it. Is the following Hadith: Islam wipes out all that has gone before it (previous misdeeds), applicable to me? Please advise me, may Allah reward you.

A: To be on the safe side, you have to estimate the amount of money which you collected from the first job and pay it as Sadaqah (voluntary charity) to get rid of it. You have to repent to Allah (Glorified be He) as He accepts the repentance of anyone who performs Tawbah (repentance to Allah).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.