ZIPPO black cotton core, it needs to be replaced?

ZIPPO 棉芯变黑了， 是否需要更换?。

youdao

Cotton core is packed by toilet paper and finalized by net embossment.

卫生纸包裹棉芯，棉芯网压定型。

youdao

It can produce air-laid paper napkin pad, fluffy N. W. fabric napkin pad and three pieces style napkin pad. (As per request, it can be added to produce cotton core napkin pad.)

可生产无尘纸护垫，蓬松无纺布护垫，三片式护垫(根据要求可增加生产棉芯护垫)。

youdao

Last September, the New York brokerage Cantor Fitzgerald teamed up with the New York Cotton Exchange to develop an electronic exchange to trade American government-bond futures, striking at the core of the Board of Trade's franchise.

ECONOMIST: Chicago��s ancient futures exchanges are showing their age