Why wash dog before shaving?

When preparing to shave a dog, the choice to bathe the dog before or after shaving depends on how short you want to shave.
If you want to shave the coat down to the skin, which is only necessary in the most extreme cases, such as severe tangles, and only for certain breeds and mixes, you should shave the coat first before washing the dog.
For clippings where the coat is easy to brush and any tangles are far from the skin, wash and dry the coat well before you begin cutting or trimming.
If you only want to shave small areas, such as around the soles of the feet, a full bathing and preparation procedure is not necessary.