It is unlikely that the dust mantles of small comets (cometary mass ∼105kg, earth impact rate ∼20 per minute) suppress the evaporation of gases into the solar wind. An order‐of‐magnitude argument based on comet sizes, densities, and meteoritic dust influx indicate a maximum thickness for the mantles of ∼200µm. A much more reasonable estimate gives a thickness of ∼0.2µm. The mantles must be considered too thin to prevent the enrichment of the solar wind b