Reda Rewoolution, the Italian merino wool knitter, has involved about 100 selected European dealers since April 1 in a similar recycling operation. Using a highly visible display and promotional flyers, it has invited customers to take any old synthetic sweater to the store in exchange for a 20 percent discount on a Rewoolution T-shirt in pure merino wool. The synthetic garments will be recycled for use through a partner in environmental projects and for aid in developing countries.