Surface must be completely cleam. dry and free of dust and oil. If applieed on plastic, polish the surface with sand paper to make it rough.

接合面必须清洁， 干燥， 无灰尘或油污， 若是塑料物件， 应先用砂纸打磨其表面， 使之粗糙。

youdao

During fracking, large volumes of water, along with sand and hazardous chemicals, are injected into the ground to break rock apart and free the oil and gas.

WSJ: Fracking coalition upsets both greens and drillers