Typically, Force sensitive lightsaber users were able to successfully parry slugs without issue.[9] However, in certain occasions, slugthrowers were surprisingly useful against lightsabers, as when a slug flying at high speed made contact with a plasma blade, it would simply melt instead of being deflected like a typical blaster bolt. Molten vapor fragments and/or shrapnel could then scatter towards the face or bare hands of the lightsaber user, and cause harm if they were not careful.[10]

https://starwars.fandom.com/wiki/Slugthrower