Easiest method of replacing antifreeze at home?

[jdheff1982]

So, ya, I need to replace the antifreeze as it is only good to +20* F and the temps are coming down close to that. I know that prestone has the cheap flush kit, but does that get the anti out of the block too or is that something I don't need to worry about when adding new anti? Trying to stay cheap with this as I have been quoted near $100 for a complete flush and refill.

Thanks.