I find it interesting that at one time, arterial "plaque" was also considered to be some sort of residue or trash. Analysis of the plaque revealed high levels of cholesterol, so the "trash" was obviously caused by the cholesterol, probably by eating too much of it. This message was no doubt approved by the tobacco industry, which produces a zero-cholesterol product that is nevertheless highly damaging to the arteries.

Now many doctors have changed their understanding: arterial plaques are scar tissue and scar tissue happens to contain a lot of cholesterol. Anything that causes scarring - like high blood pressure - leaves these plaques. So really the plaques are the by-product of an underlying pathology, which themselves create a secondary pathology.

Likewise, perhaps, with Alzheimer's. The plaques in the brain are themselves a by-product of some other pathology. Solve the underlying pathology (or the body's response to it), and you solve Alzheimer's.