I had an itch the leading edges of the wings would need work and figured I could sand / fill into the air instead of hitting the main body. I didnt dampen but I used my nail filer and stuffed the hanging cotton into the cockpit and it makes a rather nice tight cover.. like tape is holding it in [I did after those pices were taken because it was falling out]. Since cotton is the most workable material ever I just poked it like a surgeon and operated, took 10 seconds
OK, I got ya! Still a good idea to dampen the cotton anyway, as it can be an awkward little devil, and leave tiny loose strands that you can't see until the paint has dried on it! I know - I found out the hard way, years ago!!
Stuka update.. I had a light gap between main body and wings so I used super glue and a toothpick and packed it in there.. I have sanded it out and still need to do some more but no detail has been lost.. I think another round of light primer will cover it, the gap is filled but the glue is clear
Apply some putty then sanding and voila.. But I have to check it closely.In all pics of Ju-87D these aren't seen because of the the direction of a picture taking.
In TBU no.148 about Ju87D-H I have found that the first panel is exactly above the auxiliary oil tank of capacity 27l. So it can be the oil inlet.And both panels there are round as well.