Xbox one s corrosion

Hi everyone, i have one xbox one s and i traid to change the thermal paste. When i was doing that, i noticed some corrosion in the mother board (white parts). I tried to clean it whit a thoothbrush and isopropyl alcohol but when the mother board gets dry, the white parts appears back. That’s normal? It’s probably to this white parts are going to broke my console? Thanks for the responses and if i said something wrong, sorry for that, i’m from Perú and my english are bad. Regards for all!

thats normally. Its residue left over from the manufacturing process.