Soil should be tested as soon as possible following spring thaw. The youngest most fully mature leaves of suspect plants should be sampled midsummer. Request a chloride test when submitting to the laboratory and be careful to avoid contamination. Minimize plant damage by going lightly with rock salt, especially near sensitive plants, and mix with sand for better traction. Fertilizers will melt ice but are not acceptable alternatives.
Fertilizers are 'salts' and so can cause plant injury just as easily in some cases as rock salt.
In addition, nitrogen containing fertilizer are very corrosive to concrete and phosphorus containing fertilizers contribute to environmental degradation.