Do you have to use acetone to clean in between layers of laminate, or is there something else I can use to clean after sanding?

Nail varnish remover is just watered down acetone with perfumes added.  A good substitute if you want small quantities and can't find a local industrial supplier of acetone.  Most supermarkets or similar will have a budget nail varnish remover which is fine for the job.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant