The odor of smoke fumes is caused by incomplete combustion. Webster defines smoke as "the gaseous products of burning carbonaceous materials made visible by the presence of small particles of carbon", known to us as soot. The odor we are dealing with is very complex.
When a substance is burned, it releases carbon in combination with various tars, acid, resins, ect. This sticky residue aided by heat, magnetism, and impingement builds up on surfaces and creates area of odor.
That is the reason to have your possessions restored by a professional restoration company.