Identifying washington and Franklin stamps of the early 20th century can get complicated as there are several variables to take into account.
I suggest you go to
http://www.stampsmarter.com/feature...rank_ID.html to use the tool there in a stepwise fashion.
In the first case, your green 1 cent Washington.
a 1 cent of that design has a number of possibilities.
You will want to get hold of a perforation gauge to see what the perforation is, both horizontal and vertical, and then input the number(s). There is a printable one at:
http://www.stampsmarter.com/learnin...rfGauge.htmlAfter that you will be left with a couple possibilities for which checking a watermark will probably be necessary. There are some threads on the Stamp Comm. Forum about that. This will narrow the possibilities and you can report back findings to make sure you are on the right track.
Keep in mind that there were millions of these stamps produced so in terms of monetary value it is extremely unlikely that you have anything worth more than a few pennies. But there's a lot of fun figuring out exactly what you have in hand.