1) Break open 2) Break the seal of 3) Crack open 4) Declassify 5) Open 6) Open an envelope 7) Open the envelope 8) Open the pickle jar 9) Open up 10) To unseal a tomb 11) Use a letter opener on 1) Open 
• (v. t.) To disclose, as a secret. • (v. t.) To break or remove the seal of; to open, as what is sealed; as, to unseal a letter.
[v] - break the seal of
to break or remove the seal of; open, as something sealed or firmly closed: to unseal a letter; to unseal a tomb. · to free from constraint, as a person's thought, speech, or behavior: Their friendship unsealed her vivacity.