I’m not sure if this question is one for your site (and if so, I apologize), but in last week’s sedra according to Rashi, Eliezer put his hand to Avraham avinu’s milah. Isn’t that assur ? Similarly, by Yaakov Avinu and Yosef ?
Interesting question. The answer to it is that it is only an issue if it is going to cause negative thoughts, however regarding Avrohom, Yitzchok and Yosef it wasn’t going to cause negative thoughts. To them their mila was the holiest object that they had, similar to the way we regard a sefer torah. To them this was their inscription that the divine presence is with them. Therefore it was not an issue for them.