I have a simpson 7.5 kgs washing mac...

I have seen this many times. It is due to water not desolving the soaps sufficiently. It forms a blanket on the inside drum and eventually breaks away causing small particles to find its way onto your clothing. You are in a catch 10 situation because if you apply a cleaning agent or lots of hot water to flush the inner tub, it is going to get very much worse as the undesolved soaps breaks away.A technician is needed to split the 2 drums to gain access to the contaminated areas and clean properly with a HPwasher. If you decided to replace the washer, try and connect to a hot water tap or rince with hot water at least 3 times a week.