Vanish Pre-Wash Gel

I was sitting next to a pupil at work who decided he would colour my trousers with a green white board pen. I was not happy. Getting home from world I liberated my tube of vanish rewash gel from the cupboard. This gel was enclosed in a pink and white tube containing 200g. The business end of the tube has a clear cap on it. Through this you can see some pink plastic bristles these are attached to the tube of gel. I squeezed the tube and some gel oozed onto the bristles and I then scrubbed it onto the mark on my dry trousers. I had another dirty mark on them too so I used this gel on that unidentified mark too. I left my dry trousers lying ...