| The best and easiest way to use up bars of soap is to attach it to a "new" bar of soap. It depends on the shape of the bars you’re trying to attach together; the more flat the bars are the easier it is to have them adhere together. If you’re asking about rebatching the soap pieces, then it is a lot of work and not worth the extra work. Something else that some people do, is to put the pieces in muslin bags, and use them like a soap/wash cloth combo. hth | 
