Notes for specific categories
(These notes apply only to categories that specifically reference a particular note).

1) This note applies only to category "USA all-over advertising".
These covers are "all over back advertising". We are picturing the backs. The fronts may bear stamps, or they may have meter postage. Some are regular envelopes, others are window envelopes. Sorry, at this price, we can't differentiate and cannot answer questions about specific covers. Most of this lot dates from the early 1950s.

2) This note applies only to category "USA stationery advertising"
These are used postal cards, generally from the 1940s and 1950s.

3) This note applies only to category "USA First Day - Add-ons"
This is a collection of First Day Covers that the collector liked to dress up. Some have extra, uncancelled stamps or labels added, some have hand-colored portions of the cachets, or other elements that he thought were fun.