Return the stuff as soon as you can, tominator! As the ff. link will tell you, methylated spirits is just another name for denatured alcohol:
http://www.tipking.com/tip/5670.html
Now somebody correct me if I'm wrong, but denatured alcohol is a thinner for varnish, not oil-based enamels. DA is a mixture of ethyl alcohol and methyl alcohol, which are both soluble/mixable in water but not in oil. So in effect, the DA will not mix with your enamels at all. It may work as a thinner for aqueous acrylics, but I'm not sure since I haven't tried it yet. Hope this helps.
Cheers,
onyan