Buzzing due to nut

Hey guys,
When i play an open C string the nut buzzes, im pretty sure its the nut as when i sort of press down on it and play the string open (without affecting the tuning) it stops buzzing. When playing on the frets the buzz isnt heard so im pretty sure that its the nut. What can i do? i've looked at the sticky thread heres an excerpt about nut issues:

"Nut issues: Symptoms 1, 4, or 7 from the list above.
Check that nut slots angle back and down towards the tuners. Check that there is no loose plastic/tusq/bone in the nut slots. Check that slots are not too wide for the string gauges. Check that nut slots are not cut too deep causing unfretted strings to buzz against 1st fret."

Don't really understand that!
I just changed strings from aquilla to worth Brown mediums.

Thanks,
Will

I've put some bluetack on the nut, seems to have cured the buzzing for the moment, bit of a ghetto fix but it will do until i can sort it out properly. Could this be due to either the slot being too wide/narrow? (most probably the former?)

Sounds about right. If you're handy with small tools, you can partially fill the slot with super glue. A more solid fill can be done by rubbing a little baking soda into the slot and then saturating it with a drop of glue. The super glue will react with the powder and create a very hard material that can then be refiled back into shape. Use the point of a pin or toothpick to place the glue precisely. And, BE CAREFUL not to get it anywhere else.

I've gone so far as building up saddles (when I don't have a proper replacement handy) this way by making a dam out of scotch tape, filling the cavity with baking soda and doing the glue trick. It works really well.

Home Depot sells torch tip cleaning tools for about $3. It's basically a set of stiff abrasive wires in various gauges. They work like nut files at a fraction of the cost.

Hmmm, Sounds good DaveVisi, the baking soda trick sounds great, i shall have a shot at that i think! I got quite a few files and other bits and bobs around the workshop, hopefully i wont have to go out and buy anything!