Actually, the slaying mods aren't covered in much detail on the components guide, at least not on the OP.
There have been reports of 20% demonslaying sword pommels going for 100k or more, but I haven't heard of one recently. (I could've simply missed it, who knows.) I bought a 20% demonslaying pommel for 25k when I was building my slaying collection. I've seen multiple players try in vain to sell one for even that much when they started threads. I've seen a couple on Guru get offers as high as ~30k or so in the past several months.
There were (perhaps still are, not sure) a fair number of guilds farming DoA in speed clears using warriors to deal the bulk of the damage (it was referred to as "manly way.") I can't say for sure, but it always sounded like the ~100k prices for these were coming from folks with plenty of money to spare in such guilds who wanted the mod ASAP. There may still be similarly motivated buyers here and there, but don't be surprised if people aren't lining up to buy yours.
If I had a 20% demonslaying sword pommel to sell, I might spend some time looking for rich buyers, but I wouldn't feel like I'd undersold it for 20-30k.