Teardrops n Tiny Travel Trailers

I have a couple of sheets of luan that are a little scratched and need to be cleaned before I use them as the interior roof.

I read that cleaning with water will delaminate them.

Any ideas on how to clean?????......Sanding with 420 grit???

Thanks,

Howdy,
Not exactly sure what you mean by cleaned.
Scratches are not dirt, so I am assuming that you mean to remove the scratches. I am also going to assume it is either less than 1/4 " or 1/8 " thick MM measured ply.
Luann should not de-laminate with a little water, i.e. like a moistened Q tip to raise the grain in the scratch. Most all Lauan I have seen has used moisture resistant gluing. However, the interior wood has always been full of voids and very soft wood in my experience. That prevents it from being rated for exterior use. The soft inner wood could lead to swelling if soaked and the non-water PROOF glue, which would lead to a de-lam. I would try a scrap and soak it in water for a test.
All the Lauan that I have has very thin skins for the top layer like most face wood veneer plywood, think hollow core doors, approximately .5 mm thick, so sanding would have to be with very fine paper. You are going to run though quick. If it is going to be highly visible, as like britework on a boat, Buy some new laun ply. Otherwise fill with some wood putty or some bondo and fair and paint over it. Its cheep.
My recommendation : Use the scratched panels for some other place.