Young planetary nebulae (PN) which are still optically thick in the Lyman continuum can have a large fraction of material in neutral halos surrounding the ionized zone. The cool dust in the neutral region can make a significant contribution to the far infrared flux, reducing the derived dust-to-gas ratio. This is important when attempting to understand the apparent decrease in dust-to-gas ratio with nebular radius (age) suggested by Pottasch et al. (1984).