I Personaly wouldn`t do it myself, with or without tin foil, it won`t make a jot of difference.
bakelite is a thermosetting plastic, and although once set it becomes altered in a way that heat won`t re-melt it, it WILL decompose and lose its nature over time with heating.
Brittleness and cracking is the most common effect (and a slight Ammonia smell too).
100-150c isn`t a problem in everyday use, above this over a duration and it`ll denature, and not in any visible way at 1`st.
Katherine Snow. xx