Add punctuation: A drop or two on the wrists temples or forehead is a great way to enjoy the aroma for this purpose
A: A drop or two on the wrists, temples, or forehead is a great way to enjoy the aroma for this purpose.

Add punctuation: Riemann came close to proving the result but the theory of functions of a complex variable was not sufficiently developed to enable him to complete the proof
A: Riemann came close to proving the result, but the theory of functions of a complex variable was not sufficiently developed to enable him to complete the proof.

Add punctuation: They are a UK based web hosting domain registration and colocation company
A:
They are a UK based web hosting, domain registration and co-location company.