When making soap ball from dowel soap...? ...what can be put in to exfoliate the skin or administer added...

...what can be put in to exfoliate the skin or administer added soothing smells for relaxtation? The only suggestions I own found so far are orange peel, oatmeal, and bran. Can I put spices with strong sweet scent in the soap and it still be without risk used?

All answers with reliable information will be greatly appreciated.
Answers:    Here's a few but if you jump to the link it will dispense you lots of ideas almost colors too!

We used poppy seeds and I love it!!!

Patchouli
Poppy Seeds
Pumice
Almonds (ground)
Clays (rhassoul, kaolin, bentonite, pink, red moroccan, french green etc.) - more for color, though they do donate gentle cleansing/exfoliating Using Clays contained by Soap
Coconut Flakes - sprinkle some on top or incorporate in the soap
Corn Meal - Gardener's Soap Recipe
Fruit Seeds (cranberry, blackberry, blueberry, strawberry, apricot etc.)
Jojoba Beads
Oatstraw - impart a light green color too
Rosemary
Sunflower Petals
Tapioca pearls - (seems to work best contained by melt and pour soap)
Walnut shells - (finely ground)