Wall cavities are rare here, but even in solid brick walls you can find newspapers. Often when there are big holes people stuff them with paper and then plaster them over, in order to save plaster.
Floors are a great source for stuff too. The typical Vienna floor is a typical wood floor with beams and 1" subfloor, but some more layers on it. Atop of the first subfloor you get a layer of "insulation", basically sand, mixed with everything they had around. That layer can be up to 12" thick. In that debris fill I found newspapers from the beginning of WWI, small bottles (one half full with antique bronze paint), lit matches the ton (pink dyed wood), even some unlit (with yellow heads), the weirdest thing a pair of ragged canvas shoes, just like red converse.
