I use steel with a non-heat-conducting handle.

With silicone, there's no telling what it is contaminated with. Refer to DOI 10.1016/j.polymertesting.2016.09.021 titled "Extraction, confirmation, and screening of non-target compounds in silicone rubber teats by purge-and-trap and SPME combined with GC-MS" (2016).

Large discussion 16 days ago (475 points, 844 comments) https://news.ycombinator.com/item?id=41996156