How would I remove this stem to replace it?

I get wanting to reuse stuff, but honestly, I wouldn’t trust an old packing nut after it’s been off. Even if it looks fine, metal fatigue or tiny cracks can cause leaks later. Vinegar might clean up the surface, but it won’t fix wear you can’t see. For a couple bucks, new is just safer - especially when water damage is on the line. I’ve seen a “good” nut fail and it’s not worth the risk.

I get the concern about leaks, but honestly, I’ve reused packing nuts a few times and never had an issue. Maybe I’ve just been lucky, but if the threads aren’t stripped and there’s no visible damage, I don’t see the harm in giving it another shot - especially if you’re in a pinch or the hardware store’s closed. Worst case, you keep an eye on it for drips after turning the water back on. Not saying it’s always the best idea, but sometimes you gotta work with what you’ve got. Water damage is a pain, though, so I get wanting to play it safe. Just feels wasteful to toss something that still looks solid.

Yeah, I get where you’re coming from. I’ve reused packing nuts too when I didn’t want to make another trip for just one part. As long as it’s not chewed up, seems fine to me. Just gotta keep an eye out for leaks, like you said. Sometimes being practical wins over being overly cautious.

I get wanting to save a trip, but honestly, I’ve had reused packing nuts bite me later. Sometimes they look fine but end up leaking after a week or two. I just grab a new one if I’m already at the store - saves me the headache down the line. Guess it depends how much you trust the old part.

Yeah, I’ve learned the hard way too - reusing old packing nuts can seem like a shortcut, but it’s not worth the risk. If it leaks, you’re right back under the sink, and probably at a worse time. I usually just swap in a new one if I’m already making the trip. That said, if the old nut looks perfect and threads smooth, I’ll sometimes chance it for a quick fix, but only if I know I can keep an eye on it. Just not worth a call from a tenant about a drip at 2am...