Salam Shahmatt
I know u asked brother Joseph's opinion, but if I may, the quranic requirement of slaughtering in Allah's name is only required for food, if u r not eating the animal derived products, then there is no requirement for halal or haram, as in there is no halal or haram leather.
In case u r referring to cheese where rennet is used or jello where gelatin is used, it is better to steer clear if u know for sure that the animal was not slaugtered in an islamic manner, these are grey areas, and most ppl prefer to avoid them so as to not commit a sin unknowingly!