What's a really good spell for beginners?

Wingardiam Leviosa. You need a wand. Wave the wand and say "winGardium leviOsa". Watch the Harry Potter movies for more clarification. Another good one is "alohomora". Opens locks. Very handy. As per the purifying ritual, try washing your hands. 20 seconds, soap, warm water, scrub gently. Repeat if you're OCD.