Resistors with lead-free coating
The coating on the leads is typically tin.

For Pb-free components, the manufacturer will have used Pb-free Sn, for example the datasheet for some resistors I picked at random says:


  Pure tin plating provides compatibility with lead (Pb)-free and lead containing soldering processes.


Presumably by "solder with lead" you mean solder with tin/lead solder (e.g. 60/40 or 63/37). There will be no need to remove the coating.