Ruined brushes when using Masking fluid

When using Masking fluid :

To save your brushes just put a little soap on your brush first.

Then use the masking fluid.  When you have finished wash your brush out with cold water.

I actually use specific Masking Fluid brushes, but any suitable brush will do.

(note: never use warm or hot water for cleaning your brushes - the bristles are held with some glue in the ferrule and that would melt in warm or hot water, guaranteed to ruin your brush)!