How do you clean warangka interior?

[Neo]

If a keris keeps getting new rust spots even though you've cleaned it thoroughly with WD 40 and it looks clean afterward, is it reasonable to suspect the warangka is polluted? Perhaps the mranggi who last did the job on the warangka accidentally dropped some sweat inside?

Assuming you do need to clean a warangka, what would you do aside from calling a mranggi? Is there any quick home-fix solution to remove salt and other debris from the interior of the warangka?

By the way, selamat Idul Fitri untuk semua yang merayakan

Edit P.S.: I've searched the forum and I found that having some "plastic condom" to wrap over the blade to be a good idea to protect a blade from polluted warangka. However, it just feels more comfortable to be certain that the warangka is safe and clean ... especially if you want to bring the keris outside and be seen by others, it will look better without the condom