Hi,
Smelling such strange smell can be present in certain conditions and it is termed as Parosmia (abhorrent odor perception).
It is usually associated with rhinosinusitis, head trauma, viral infection, or oral problems.It can also be due to damage to the smell-sensing cells in the nose (due to trauma/surgery), an infection of the nasal sinuses, a nasal poly, a structural defect or abnormal thinning or thickening of the inner lining of nose, an exposure to toxic radiations or chemicals (such as lead, those in insecticides), an epileptic condition, certain disorders of brain stem, certain psychological & psychiatric illnesses (esp. schizophrenia), smoking or alcohol intake (or even after their recent quitting) etc.
Please do consult an ENT surgeon for the same and get it examined. I sincerely hope that helps. Take care.