One way the Chinese may have practiced inoculation (also known as variolation) was by scratching matter from a smallpox sore into a healthy person's arm. Note that the source uses the term vaccination here, which is incorrect.
The Historical Medical Library of The College of Physicians of Philadelphia. The History of Inoculation and Vaccination for the Prevention and Treatment of Disease. Lecture Memoranda. A.M.A. Meeting, Minneapolis. Burroughs Wellcome and Co. London, 1913.
The Historical Medical Library of The College of Physicians of Philadelphia