Can the disposable oil and wick cups used on chanukah or shabbos be used lechatchila? Are there opinions that say not? What if the cup is made from glass or plastic which can theoretically be reused if need be by adding more oil and wick?
I don’t see any problem with disposable wicks and cups. All wicks are ‘disposable,’ and all wax candles, which are kosher for use on Chanukah, are of course used only once. Likewise, many use pre-prepared disposable cups of olive oil, and there is nothing wrong with this.
The restriction on using clay for the Chankah menorah is because after it is used once with oil, clay becomes ma’us, and it is therefore wrong to use it again. While clean, however (the first time), it can be used, and there is certainly nothing wrong with disposable cups etc. which are clean and respectable.