What happens when you mess it up...get hurt...fall through ceiling....get sick/bit (when you discover the exclusion didn't work)...burn house down...get heat stroke......get exposed to asbestos. Figure, the neighbor won't be any help and you will do it all. Did I miss anything?

When I see questions or hear about fogging, red flags start popping up in my head. When most people think of fogging, they begin thinking of billowing smoke similar to what is seen with a smoke machine or mosquito fogging. In reality, what most companies are referring to isn't fogging at all, it is atomizing -hence the first red flag.

Now the question becomes, why is atomizing being done in the first place? If you look at Steri-Fab (one of the best cleaning agents available), you can't even run it through an atomizer. Instead, you need to spray it on the area that needs to be disinfected at a concentration that will leave the surface wet for a minimum of 10 minutes. The same is true with a good number of the mold killing agents available which generates the second red flag.

Clean outs can vary greatly between companies along with the belief of what needs to be done or left alone. First, how much guano is present and why does it need removed (the Center for Disease Control recommends NOT removing guano in certain situations so what makes this a "removal" job), third red flag. Second,what type of insulation is present (there are different removal methods for different types) and is there a possibility of asbestos, lead, copper, or zinc dust, fourth red flag. You mention that the neighbor plans to double dampen the insulation to which I have to say "Huh?" and that a HEPA vacuum will be used. Wetting down guano to prevent spore dispersal I understand (CDC recommends formaldehyde as the wetting agent), wetting down insulation I don't, fifth red flag.

There are different types of HEPA vacuums on the market so unless he's planning on spending a good amount on one, it most likely that he is planning on buying a shop vac with a HEPA filter, sixth red flag. A true HEPA vacuum will be a closed system with a minimum of three filtration points. The problem with them is that due to all of the filtration, they are normally rated for fine particulates only. In other words,they don't have the power to sweep up insulation. Even a regular shop vac with a collection bag will have problems vacuuming up insulation, especially if it can even be wetted down. This is why clean out companies spend thousands of dollars on insulation vacuums and then they do find cleaning with smaller vacuums.

Just to get on with this, knowing what type of respirator is needed and how to use it, body coverage requirements, bagging requirements, air flow containment and possible filtration (negative air flow), clean room, movement of contaminated materials and disposal are all part of this process and I didn't even touch on odor control, removal/repair of contaminated materials (aside from the insulation) or bat bugs.

Instead of suggesting that someone not try to do something, I find it better to give them enough information and/or point them in the correct direction so they can see what is truly required to do what they are considering doing. When it comes to clean outs, basic information can be found at CDC.gov when searching for histoplasmosis (look for the small business guide with respirators, it's about 80 some pages long), do some research on mold remediation (a good starting book is "The Homeowner's Guide to Mold"), and also look at some of the free training on the OSHA website or links looking for General Industry, Respirators, Industrial Hygiene, and Confined Space. While everything previously posted could happen to you or your neighbor, they sure as heck can also happen to a company that has been hired to perform the clean out. There are certain companies that will always be better than other companies simply because they put in the time, training, and practice to be better. If a half attic or more clean out is required, he is probably best off by hiring a company to get it done, but if he has a couple of pieces of bat guano here and there throughout the attic he most likely doesn't need to do anything with the attic.