Common Sentence Level Problem

• Comma splice. Commas do not join, they cut.

Example 1: Could you rewrite this sentence by eliminating the ‘and’s’?

Proposals are to be submitted in duplicate, and enclosed in a sealed envelope, and endorsed with a reference number, and shall be lodged at the address below.

Proposals are to be submitted in duplicate, enclosed in a sealed envelope. They should be endorsed with a reference number. It shall be lodged at the address below.