Q. Is it better to light a silver menorah using its own silver cups by placing the oil and wick in them, as was done in the menorah of the Beth Hamikdash. or can one use separate glass cups which is cleaner and more convenient?
A. Chesed L’Avraham (quoted in Kaf Hachaim 673: 60, Sdei Chemed – M. Chanuka 7) mentions a list of fifteen different materials that can be used for crafting a menorah. The preferred top of the list material is gold, followed by silver, while the bottom or least desirable is the bark of the alon tree. Glass is in the middle as number eight.
Therefore, Shevet Halevi (8: 157) argues that one should preferably not light in the glass containers but rather on the silver menorah itself.
However, some Poskim maintain that the small glass containers become batel or annulled to the menorah itself and are essentially part of it. (Shevet Hakehossi 3: 201)
Horav Shlomo Miller’s Shlit’a opinion is that the glass cups besides being considered part of the menorah, are also an enhancement and contribute to the pleasant appearance of the utensil and can therefore be used lechatchila.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a