Seal tabs.... thats what you need

http://www.angelfire.com/biz/seallock/sealtabs.jpg

eggs work but dont do it because it will go very hard and wont come out

I've used the Wynns Radiator stopleak product before, and found it works really well, it stays fluid so can never block up the cooling system, but can be flushed out once you can afford to fix it properly. It also works well as a preventative to seepage around hoses caused by antifreeze.