An egg wash is a light coating of diluted egg – usually 1 – 2 Tab/egg. It is brushed onto the dough  prior to  baking.  There may be times when you cannot use eggs either you don’t have any,  you have allergies, or because you choose not to consume eggs. Leaving the dish without a wash may leave it dull and pale.

Milk or Cream – brush some cream or milk to get a crisp golden color.
Melted Butter – melt some butter in a bowl and lightly coat your food with it.
Honey, Maple syrup, Malt syrup, Molasses – these liquid-gold sweeteners will to do the same trick.
Egg White Only Wash –  you can always choose the egg white only wash.
Golden Yolk – for  a bolder glaze and color, skip the white and go straight for the yolk.
Almond Milk – almond milk will give a similar glaze as milk, with a light hint of almondy nutty taste.
Oil – Flavorless oil or olive oil wash will give the food more of a shine along with the golden brown crisp exterior.

Source:   tastessence.com