1.   He put the letter in a plain brown envelope.

2.   It came in a plain white envelope with a New York postmark and had no return address.

3.   My name and address were printed in a bold black type on a plain white envelope.

4.   But his favorite phonies were the pols, the crafty, grafty suits whose own leg men ran the plain brown envelopes of payoff money.

5.   But, as had happened many times before, a vague response came in a familiar plain white envelope from Montana.

6.   Direct mailers are replacing plain envelopes with preprinted ones, contacting customers by e-mail and telephone and more thoroughly investigating clients who wish to buy their mailing lists.

7.   The letter, which appeared to have been printed out from a home computer, arrived in a plain envelope with no return address.

8.   The plain white envelopes with block letters were inconspicuous, except for the lack of a postmark.

9.   The request was in the form of a first-class letter inside a plain white envelope with no return address.

10.   When Koga withdrew the Duerer and Rembrandt drawings from a plain manila envelope, he was arrested.