To answer your original question. I use AutoGlym products and this is their advice which I follow to clean my alcantara:
"What would be the best product to clean alcantara?
We recommend Interior Shampoo which should be applied to a damp cleaning cloth - NOT sprayed onto the fabric directly. The Alcantara
cloth should only be wiped very gently to clean the surface and then wiped gently with a clean cloth rinsed out in fresh water. Never rub
harshly or the nap of the fabric will be damaged and avoid over wetting."
http://www.autoglym.com/valeting_bay/faqs/59-What-would-be-the-best-product-to-clean-alcantara