Wikipedia informs me that the first papers used a laser (https://www.nature.com/articles/318162a0 - "graphite has been vaporized by laser irradiation, producing a remarkably stable cluster consisting of 60 carbon atoms") (1985) and the arc welding approach was a few year later. The paper "Solid C60: a new form of carbon" (1990) paper describes using benzene to dissolve the soot to extract the C60 (https://heyokatc.com/pdfs/MISC/Solid_C60-_a_new_form_of_carb...).