用纯的半奶油半牛奶，或者鲜奶油替代蛋液。 用橄榄油替代蛋液。 去超市购买蛋液替代品。

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
If you'd like to leave the egg out of the wash, you can still add golden color to your baked goods. Brush half-and-half or heavy cream on your baked goods for a matte finish. Keep in mind that the heavy cream is more likely to crack as it expands. Olive oil is a good vegan substitute for egg wash. Just brush pure olive oil directly on your bread or baked goods. While olive oil will give your baked goods a little shine, it may give a faint olive oil flavor so avoid brushing it on sweet baked good