I have an attic that makes me sick to death to go up there without a respirator. 

One tip from EMS when you're dealing with odors that nearly drive you out of the house, and you don't want to use a respirator: a dab of vicks vapor rub under your dust mask.

If you do go the chemical route, make sure you have good gloves, a respirator, glasses (a splash or drop in your eye will be a memorable experience) and a strong back.  

Get shellac (and a special respirator) to seal in the smells.

Popcorn requires more extensive measures - you'd be fine wetting it down and scraping it while wearing a respirator, but the law requires certifications, testing, blah blah so we typically just leave the popcorn in place in those homes.

I've driven by houses that I no longer own that I painted 10+ years ago and they still look fine.As far as asbestos siding, I would wear a respirator and use a lower pressure setting on the nozzle.

But make sure you use a REALLY GOOD respirator if you are going to go this route. 

And they make organic vapor cartridges for respirators, you won't smell a thing!

It was so bad inside after cooking for 9 months that 10 seconds inside without a respirator and you'd come out gagging. 2 weeks later after stumbling across BP, reading and listening to Podcasts, I decided it would make a killer investment property.

It's nasty stuff and a regular face mask won't cut it.Use a respirator that is specifically designed for mold, like this one:http://www.homedepot.com/p/3M-P100-Medium-Mold-and...It's short money for good protection.