So I have a DSE901 and I look at the carts themselves and I see some wool. I've seen the dripping techniques but that could be a hassle over time so I've opted to instead just fill some cartridges. The only thing is, I don't know what people usually do to add in other liquid. Do you guys wash out/remove the wool from an already used up cartridge and just "pour" some new liquid in? Do you just drip onto the wool of another cartridge (with the wool)? I'm trying to find some US distributor of an empty cartridge for the DSE901 but can't find one... (if that's the easiest way)