Methods of preparing ruthenium carbene complex precursors are disclosed herein. In some embodiments, the methods include reacting a ruthenium refinery salt with an L-type ligand and a reducing agent to form the ruthenium carbene complex precursor. Methods of preparing a ruthenium vinylcarbene complex are also disclosed. In some embodiments, preparing a ruthenium carbene complex includes converting a ruthenium carbene complex precursor into a ruthenium carbene complex having a structure (PR1R2R3)2Cl2Ru═CH—R4, wherein R1, R2, R3, and R4 are defined herein.