keep centered

I was given a batch of homemade soap. A lovely lavendar variety. The problem was that they were in ugly, lumpy shapes. So being a geek I wanted to re-shape them. I melted the soap down and cast it in molds. First batch came out well. I remelted the soap & cast the second batch but even after a long wait are still bottom-of-the-soap-dish gooey. Any ideas on how to get the rest of the soap to set up?