Question

why do you need to wipe off excess stain, and when should this be done?

Explanation:

Excess stain can cause uneven coloring and unwanted buildup. It should be wiped off after the stain has had enough time to penetrate the material but before it dries completely. This ensures a uniform finish and prevents blotches or overly dark areas.

Answer:

Excess stain needs to be wiped off to avoid uneven coloring and buildup. It should be done after penetration but before drying.