For those still in the broom closet, and for those who simply don't want to attract unnecessary attention, magick can be rather difficult to perform in public. As such I've decided to compile a list of undercover tools that can be used in a pinch.
Compact mirror--many women carry these in their purse anyway. This item does tend to be a bit more challenging for guys to work-- sorry guys. This tool is possibly the best known undercover tool. You can take it out of your purse pretending to check your makeup, and do a quick mirror spell or scry.
A deck of cards--as these are based on the Tarot cards, this should be pretty self-explanatory. Its also great for when you're stuck someplace and bored.
Jewelry--These are perhaps the most multi-purpose undercover accessories. Any piece of jewelry you own can be charged, made into a talisman, etc. In highschool I used to make quartz point pendulums that could double as necklaces.
Pocket/Swiss Army Knife--Athame anyone? Plus they're just downright useful.
Clove Cigarillos--Surprised? Don't be. The herb Clove has amazing protective/exorcism properties (not to mention love and money). Find yourself being followed by some negative energy? Run into a nasty spirit somewhere? Light one of these suckers and blow the smoke in the unsavory's direction. You don't even have to really inhale, just suck some smoke into your mouth and puff it out.
Lighter--I know, I know, the energy really isn't the same as wooden matches. That being said, sometimes a wooden match just isn't practical. There a breeze out? You can't get something to light? You can run through a half box of matches before what you need to light is lit. Bic lighters (and other such) also work as a light source in a pinch.
Pen+Paper--symbols, desires, intents...all of these can be written down. Granted, lighting in on fire right then and there usually isn't the brightest, but you can tuck it into you pocket (or into a bra--I find keeping the intent close to my heart helps) and it should do the trick.
Empty Perfume/Cologne bottles--These can be refilled with any sort of potion or aromatherapy something-or-other you desire.
Don't forget the power of visualization! When push comes to shove, you really don't need any tools (though they can help). Your imagination is the greatest tool you have.
Have some ideas? Did I forget something? Go ahead and shout 'em out! Its always useful to know what resources you have.