How to clean a dirty bike chain?

I have a really dirty gummy bike chian that probably been there for years. I forgot to buy degreaser from the bike store and I don't have time to go back. I don't have any bike cleanining tools. I was wondering if there were something I can buy from the grocery store that can clean my bike chain. I try using a rag with ajax dish washer, but that was no good. I was thinking about using dawn. I heard their good with grease. Is there something that is really good against dirty grease for cleaning in a grocery store or something? Like CVS or rite aid or something and if so what brand?