Abstract: Bag closure 100, formed from a single length of pliable, resilient substantially-tubular hose comprises a first “base” section 10 of unmodified hose, a second narrowed “neck” section 20, and a third “clamp” section 30. Clamp section 30 is a trimmed section of hose having a substantially C-shaped cross section, formed by removing a narrow strip of hose material parallel to the hose axis. Hinge 20 is a trimmed section of hose having a substantially parenthesis-shaped cross section, formed by removing a wider strip of hose material parallel to the hose axis. A bag neck may be sealed by laying the flattened bag neck across substantially-cylindrical base 10, folding the closure at its narrowed neck or hinge 20 and forcing clamp section 30 over base 10, trapping the bag neck between base 10 and clamp 30 and forming a tight seal.