Responsa for Shabbat 288:14
כדאמר ר' יוחנן בטיפה המלוכלכת ע"פ הדד הכא נמי בטיפה המלוכלכת ע"פ הדד
is unclean? Because it cannot but contain particles of diluted oil. Wherein do they differ?<span class="x" onmousemove="('comment',' Since both admit that the first fluid is clean, while that which oozes from the olive pulp is unclean, in respect of what do they disagree? ');"><sup>26</sup></span> They differ in respect to what oozes after [the olives have been subject to their own] pressure. Raba said: The reason is because it is something whereof a mikweh may not be made, and such renders a mikweh unfit through change of colour.<span class="x" onmousemove="('comment',' That is why the serial fluid makes the mikweh unfit; accordingly that ruling agrees with all. ');"><sup>27</sup></span>
Maharach Or Zarua Responsa
R. Hayyim Eliezer recalls that one time, the winterhouse was once heated by a Gentile on the Sabbath, and his father refused to eat therein. R. Samuel of Falaise in the name of R. Yom Tov permitted one to dwell in a winterhouse that was warmed by a Gentile on the Sabbath. In our city, most of the people rely upon this decision and dwell in winterhouses that are warmed by Gentiles on the Sabbath.