我又想問點解一部分護膚產品{同一牌子}有d用膠樽裝有d用玻璃樽裝?

Sometimes the reason for choosing a packaging material is cost-related, i.e., the cheaper the better.

At all times compatibility is important. Certain substances are able to penetrate or permeate or dissolve the packaging material, therefore resulting in "leakage". In this case, a compatible packaging material must be chosen.

I am not entirely sure, but 精華油 may be a kind of solvent which dissolves certain plastic.