I don't know if anyone else has stumbled across this . I didn't care for how cluttered my aircraft folder was getting with extra decals so I tried some thing.
I added a new folder, inside the aircraft folder and gave it the same name as the skin as whose decals would go into it; I named it 417 for my 417 squadron skin. inside it I placed all of the decals for that skin.
Next i opened the decals.ini folder for that skin and changed the decalfileformat line to have 417 in front of the decal I wanted to useso it looked like this:
[Decal001]
MeshName=fuselage
DecalFacing=RIGHT
FilenameFormat=417canada
Position=2.15,-0.000
Rotation=0.0
Scale=1.85
DecalMaxLOD=4
Now the decals still appear on the air craft but don't clogg up your aircraft folder this will also make uninstalling a skin much easier