From Longman Dictionary of Contemporary Englishsteam something ↔ open/off phrasal verbOPENto use steam to open an envelope or to remove a stamp from an envelope → steam→ See Verb table
Examples from the Corpus
steam open/off• It didn't hurt his conscience too much, therefore, to spend time steaming the envelope open and letting curiosity prevail.• A floating stage to accommodate two steam vessels was opened in 1880 and a floating roadway was added in 1926.• At about a kilometre's range the whales' blow looked like small globular puffs of steam rising off the sea surface.• Coils of steam writhed off the wet grass under the early heat of the sun. 