dish

A dish heater, sprays only discolor the dish and AFAIK don't do anything to prevent snow/ice from building up on the dish.  A super soacker style water gun filled with warm water will remove snow/ice.

To prevent build-up would be a dish heater. Those other ideas of sprays and such at best discolor the dish or at worst interfere with the reflective surface.

Some people use something like a "super soaker" to clear build up with warm water. Safer than using a broom to brush it off as that risks affecting the alignment. If in an area where this is an ongoing concern, an alternative is having the dish installed on a pole mount so that it is within easy reach.

solid signal has dish heaters i belive you can get manual ones and automatic ones. ide go for the automatic one where it heats up by itself and melts the snow and ice off the dish