Those will be located in M-347, Unfiled Papers and Slips Belonging in Confederate Compiled
Service Records, 442 microfilm reels.

Here's the National Archives Description --

This microfilm publication reproduces an extensive series of
papers that the War Department accumulated to interfile with the
regular series of compiled service records of Confederate
soldiers, but never interfiled. The records are arranged
alphabetically by surname and there are cross-references for
names that appear in the records under more than one spelling.
Often names that sound alike are grouped together. It may be
necessary, therefore, to search for a name under the various ways
in which it could have been entered.

The published guide reads as follows,

On the 442 rolls of this microfilm publication is reproduced an
extensive series of papers arranged by surnames of soldiers. They
were accumulated by the War Department to be interfiled with the
regular series of compiled service records of Confederate soldiers
but were not interfiled, for one reason or another. The types of items
most commonly included are card abstracts and personal papers similar
to those that are in the compiled service records of Confederate
soldiers and that are arranged by State organizational units.
In general, papers were placed in this series when their proper
filing was uncertain or there was no other place to file them. The
usual reason was that the information was insufficient or contained
discrepancies and could not be positively identified with any soldier
for whom there was a compiled service record. Other reasons were
that no compiled service record had been established on the basis of
regular service records and that the item did not provide enough evidence
to justify establishing one. In some cases a soldier may have
served in a home guard unit or other State organization never called
into the service of the central Government of the Confederate States.
Some of the items are vague as to whether they refer to a soldier, a
civilian employee, or a private citizen.
The card abstracts contain entries taken from original muster
rolls, returns, rosters, payrolls, inspection reports, hospital registers,
Union prison registers and rolls, and parole rolls. Also included
are references to original records, letters, vouchers, requisitions,
paroles, and oaths of allegiance. The personal papers are
the originals of documents relating solely to the particular soldier.
The compilation of service records of Confederate soldiers was
begun in 1903 under the direction of Brig. Gen. Fred C. Ainsworth,
head of the Record and Pension Office of the War Department. Abtracts
were made from documents in the War Department Collection
of Confederate Records and from documents borrowed by the War Department
in an effort to obtain as nearly complete military service
records as possible. The abstracts made from the original records
were carefully checked to ensure that the abstracts were accurate.
The records reproduced in this microcopy are arranged alphabetically
by soldiers' surnames, including variant spellings of a name
and often a grouping of names that sound alike. It may be necessary,
therefore, to search for the name under the various ways in which it
could have been entered. There are cross-references for names that
appear in the records under more than one spelling as shown below:
Caywood filed with Cawood
Chadick filed with Chaddick
Freer filed with Frear
Hollus filed with Hollis
Ratleff filed with Ratcliff
There are also guide cards showing how similar-sounding names are
placed together. A guide card for the name Barton, followed by the
names Barten and Bartin, shows that the records for the last two
names are with the name Barton in its alphabetical position in the file.
Other examples of such combinations are as follows:
Alford: Alfred, Alferd, Allford
Barber: Barbour, Barbiere, Barbor, Barbia
Barry: Barrey, Barrie, Bary
Coleman: Collman, Colman, Colmon, Coalman
Holcomb: Holcombe, Holcom, Holcome, Holcum
Hughes: Hughs, Hues, Hewes, Hughe, Hughse, Huges
Mahoney: Mahony, Maheney
The records reproduced in this microcopy are a part of Record
Group 109, War Department Collection of Confederate Records. They
are not indexed in the State indexes or in the "consolidated" index
described elsewhere.

The message board research service advertised above can search these records for particular names. These records are not currently available through Ancestry or any other pay-for-view on-line service.