Cleaning inside or rear qaurter panels

My 1/4"s(inside the trunk) have that texture paint on them,its a 25 yr old resto..Its tor-red,,the inside of the trunk 1/4"s are dirty,,what would be the best way to clean them,,they are ROUGH,,,,I dont want to introduce a bunch of water in there,,,I tried once a long time ago by stuffing towels down in the crack and washing them but no good,,,thanks,,,

Depends on how dirty. Damp softer sponge with some soap cleaner; but not too wet to drip alot. Otherwise I'd just wash/scrub & let water drain at lower drain hole. Pick a nice hot/sunny day, leave lid open, & should dry up soon. Rusting is only going to happen if areas become wet & aren't allowed to dry in a respectable time

^^^^^^^ this.

I can almost guaranty you that there is some surface rust down in there regardless of how the car was restored or maintained. So I'd avoid using any water. Instead, get at it with compressed air - a thin piece of hose on the end of a spray nozzle will give you better access and won't damage the painted surfaces. Blow out any crud and then wipe any area you can easily access with a DAMP rag. Remember, if you can't see it nobody else can either!

If you're trying to clean up the quarters, stuff towels down into the trunk extensions. Then use something like Spray Nine on the quarters and a soft scrub brush then a wipe with a damp rag to clean up. The towels in the extensions will keep the dirt and water from getting down in there.

So how did they get so dirty in the first place ???

Are you sure it's textured paint, or body color paint over factory undercoating there.
If it's really ruff, probably factory coating.