Re: 48 Star Flag
.
GREETINGS, DennisPippin !!!
Welcome to the USA-Flag-Site Forums !!!
Judging by the condition that the Flag's label is in (Very sharp & clear), it appears that your Flag might not have ever been washed/cleaned before. Or if it has, then only once or twice, and probably only "hand-washed".

IMHO - IF you choose to wash your Flag then do so ONLY by hand. Do NOT machine wash it. Use as MILD of a detergent as you can, such as "Woolite". Do NOT put it in a dryer and do NOT hang to dry. Instead, lay it flat on some towels and smooth out any wrinkles without stretching the material.
Do NOT be surprised if someone here advises you to NOT wash or clean your Flag. There is something to be said about the importance and value of "original condition".
Your Flag is probably over 50 years old and should be considered an "antique". Judging by what can be seen in the picture you provided, it looks to be in pretty good shape. If you want to keep it that way, treat it gently and, of course, with respect.
I might be wrong, but I believe that because it's Stars are appliqued and not embroidered it might be closer to 60 or 65 years old. The "down side" (if there is one) is that 48 Star Flags were "official" from July 4th, 1912 to July 3rd, 1959, so there were millions and millions of them made during that time.
There are some MUCH more experienced and knowledgeable people here than me, so do NOT base any opinions or make any decisions about your Flag on solely on what I've written here.
If you want to get a sense of your Flag's current "market value" then you might do a search on eBay and/or Google using search terms associated with your Flag (check the Flag's label). Something like : Dettra Bulldog bunting "moth-proof" "48 Stars", etc. Start off simple with something like "American Flag" +Dettra +"48 Stars". If you can't find anything similar to yours listed on eBay, try the "advanced search" mode and select "Completed Listings". If there were any listed, you can find out what the "asking prices" were, and if any were sold, what they were sold for. If you don't find any, be patient and persistent, and keep searching!
Off the top of my head, I think the 3'x5' 48-Star Dettra U.S. Flags that I've seen on eBay over the past couple of years have ranged from a low of $10-15.00 all the way up to $50-60.00. Perhaps a little higher.
I hope you'll post a few more pictures of your Flag here. Show us a little more of the "color", construction details, needlework, etc.

I hope I've been of some small assistance, but remember what I said earlier: there are MUCH more experienced and knowledgeable people here than me who can give you additional information and advice about your Flag !!!
Thank You for bringing your Flag-related question to our Forums !!!
Robin Hickman
Eugene, Oregon, USA
.
"All That Is Needed For Evil To Triumph Is For Good Men To Stand By And Do Nothing"