In some cases you can.
Removing asphalt shingle siding.
Removing asphalt shingles is a big job and you might be temped simply to lay the new roof over the old one.
Merely removing a nail and taking down a siding shingle will not place you in grave danger or any kind of danger.
But because one thing often leads to another i e merely removing a nail leads to the temptation to smash a shingle to remove it all because the nail won t come out we are issuing the full set of safety warnings.
It is not uncommon for roof shingles to turn black over time.
Bob the secret material you are looking for is called dewitts remove it it is a citrus based cleaner in a pump spray bottle and works great on vinyl and aluminum siding i am a roofing contractor in akron ohio and over the years i have tried wd 40 choke and carb cleaner kerosene acetone tsp mineral spirits paint thinner and any other cleaner or solvent you could name all were unsatisfatory.
When that happens it is generally caused by mildew algae mold or dirt stains.
The hard brittle shingle siding and roofing that was used on many homes before 1980 often contained asbestos and should be tested before being disturbed or removed.