FAQs: The Brown Scapular
Sisters of Carmel
https://www.sistersofcarmel.com/faqs-the-brown-scapular/

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10. How must I wear the Scapular in order to receive its benefits?

You must wear it over the shoulder so that one part hangs over your chest and the other side hangs over the back. Both parts cannot be carried in the front or the back, otherwise, the wearer runs the risk of not receiving the promise.

11. May the Scapular be fastened or pinned to my clothing?

The Scapular must hang over the shoulders with one side hanging in the front and the other side hanging in the back. However, one may sew or pin the scapular to an undergarment to hold it in place or to keep it from rising about one's neck.

12. What if I'm allergic to wool?

If one has a serious allergy to wool or has irritation of the skin, one can wear the wool scapular over one's clothing, encase the wool scapular in plastic, or wear the Scapular Medal with an image of the Sacred Heart on one side and an image of Our Lady on the other side.

13. Does the Scapular have to be 100% wool?

Yes. Cotton, silk, and any other material is strictly forbidden.

14. May I use a chain instead of a cord for my Scapular?

Yes, just as long as the scapular itself is 100% wool.

15. What shape does the Scapular have to be?

It must be rectangular or square. It cannot be oval, round, or polygonal.

16. May the Scapular have any other images on it?

It is permitted to ornament the Scapular with images or pictures, such as Our Lady of Mt. Carmel or the Carmelite shield. However, the wool brown color of the Scapular must predominate.

17. Does the Scapular have to be touching the skin?

No, it may be worn over or under any part of the clothing.