Cleaning cement steps to remove blackish stain (may be shingle tar?)?

If you have a friend with a pressure washer try that if not try bleach and soap and scrup it with a brush and wash with hose. If it truly is a tar........then you need something that breaks that down........that can be w d 40 or gas .......but you need to wash and clean it fast as not to spread the stain....what it sounds to me like is just something that needs a good soapy bleach wash...or pressure washer..........enjoy. By the way, try the bleach and soap first.......not oil removing materials.