Anyone squatting/exploring old hospitals or industrial facilities or scrapping metal should read these pdf files. They contain information about identifying radioactive sources commonly used in these environments. Be careful out there.
http://www.iaea.org/Publications/Booklets/SealedRadioactiveSources/pdfs/flyer_public.pdf
http://www.iaea.org/Publications/Booklets/SealedRadioactiveSources/pdfs/handout_scrap.pdf
http://www.iaea.org/Publications/Booklets/SealedRadioactiveSources/pdfs/flyer_public.pdf
http://www.iaea.org/Publications/Booklets/SealedRadioactiveSources/pdfs/handout_scrap.pdf