I bought a flint/steel combo at REI a few weeks ago and tried it with a few items around the house with good success - tissue paper and drier lint both worked for me.

Like you I also wanted to try some natural tinder. So while out on one of my dirt bike rides last week I grabbed a plume of Pampas grass and stuffed that in my backpack and brought it home.

I stripped a bunch of the material from the top of the plume and piled it into a little spot on the sidewalk and with garden hose handy I set to work with the flint and striker.

Wow! I almost burned my fingers. The stuff lights very easily and burns hot and fast. The little stalks that hold the plume material then burns with a more sustained glow that you can blow on to keep going for a while.

That stuff grows all over here in So Cal. I figured that I'd look for more different materials on my next ride and continue to experiment until I've developed a reasonable list of alternates and improved my starting skills.

I'll only bring the materials home to practice in a safe environment however because one has to be really careful around here when starting a fire as the whole area is basically a tinder keg waiting to go off.