root directory being filled?

[delfinnium]

Hi all

I've had a clean reinstall of my linux mint and everything is good... until just today a thing popped up to say that my root is full.

D: I had given it 4GB when I reinstalled linux mint, leaving everything to my home drive. Now what I read is that root IS required in larger volumes.

So what can I do? I have plenty of space in /home, and I don't particularly want to reinstall everything. Where is the files where I can delete/clear my cache? How do I go about doing it?

(In nice easy steps because I can't actually find this .tmp or .var folders that other websites say I must look in.)