Can you tell me how I could remove the black aspergillus niger?

Molds. Molds like Aspergillus thrive when there are * water *stagnant air * nutrient (especially wood fiber). Damaged dry wall, carpeting, and particle board etc must be removed. Keep house well ventilated and wipe off pooled water. Clorox may kill the molds but without the preventive measures, they will come back.