A few days? What if it went a few weeks?
After burning there is not exactly much to corrode, is there? I would think that they important part would be to get it entirely clean before reloading, rather than cleaning quickly, but I am not an expert.
How about a few years?
Say.............. 12 or 13?
A cluster rocket launched at LDRS in 1999 Orangeburg was found with all motors intact,[ just a couple years ago] when the woods was being cleared for an industrial park. Nothing else but a partial fin can was recognizable.
Motors were removed and cleaned, several are still being used.
On the other hand, I've seen cases corroded beyond use, just after a year or 2, due to neglect and proper usage.
There is a reason a thin coat of grease is recommended on the liner. Besides making the liner easier to remove, it also prevents oxidation as long is there is not a liner burn through. Residue from burning contains solids that when mixed with moisture create acids that will corrode the aluminum case. Grease helps/prevents this.
A very , very thin coat......excess grease works to a disadvantage..... turning to gunk...causing the liner to bond to case, making removal after a long period of time very difficult.
Hate to admit it, but as my flying has gone from years to decades, I have become very lazy and it's common for my motors to lay around months before I clean them.
No problem though...as I always spray my cases with W-40 liberally when finished cleaning, creating a moisture barrier between the case any residue still left and moisture... the enemy.