Cleaning Indoor Air

We're certain that many are sneezing and wheezing as you read this with allergens in full force.  However, for Amy, she thinks it may be something else lurking in her house.  She writes:

We have a (very amateurly installed) air conditioning unit in our 1920s house. Twice recently, when the temps got unbearable inside (mid 80s), we turned it on for a few hours. Both times, I got a sore throat that led to sinus infection within a couple of days. This last time, my husband got a sore throat followed by a migraine (which he has never had before) the following day. Amazingly, our 9-month-old daughter didn't get sick ... but we're wondering if our ductwork needs cleaning. (All this could be seasonal allergies or coincidence, but we're still leery.) I haven't been able to find reliable information about household air cleaning services - has anyone had their ventilation systems cleaned, and did it help noticeably? Any references for a reputable company? What about air purifiers? DIY solutions? Other ideas? Wheezingly yours, Amy

Permanent Marker Stain Removal Help

Let's try to help Michelle out.  We've probably been her predicament.  She writes:

Okay. Breathe. My three-year-old aspiring artist has taken a permanent Sharpie to our light carpet! Surely, I'm not the first mama to experience this...does anyone have recommendations on a cleaner - store bought or home creation? I am open to ANY suggestions!