Racism aside, the most well known icon of dirtiness in Mexico is a character living in the streets of Mexico City known as 'El Changoleon'. Please see related links for a picture.
because they believe that pigs are dirty like mexican food
dirty
No dirty rice is from New Orleans
Your girlfriend is like a brick, flat on both sides and laid by mexicans.
dirty
Sh*t on your upper lip like a mexican's stereotypical mustache.
dirty cheese
It will look dirty. Just replace the filter every 30,000 miles.
convicts look dirty with very little food
big and dry
it was a Mexican style mission.
Look at the 'related links' section.