Caliper

Over the last year or so of tubeless tire use, it seems that I have gotten a buildup of tubeless sealant inside the valve core despite trying to ensure that there isn't any sealant in the valve when checking tires. It has gotten to the point that it is difficult to put air in the tire and the valve doesn't seal fully due to the sealant in the core. I've replaced them with a fresh pair, but is there any way to clean out the old valve cores so they can be used again?

DrIsotope

Sort of. You can drop 'em in a glass of hot water, sometimes it helps. But more often than not, it's not the sealant at all. The little rubber seal at the very bottom of the core gets soft, and works it's way up into the stem. Usually the core is shot.

I buy cores by the 10-bag, and as soon as one starts flowing slowly, it gets replaced. I go through about a bag a year, spread across three bikes.

Koyote

They're dirt cheap if purchased in packs (try Amazon), as DrIsotope suggests. Cleaning them out makes about as much sense as laundering q-tips.

Caliper

Nope, definitely goop in the core. The seal is fine. I guess I'll be getting a bag of cores and hoping that the new tubeless standards finally let this concept work without the sealant...

JohnDThompson 

Household ammonia solution is able to disolve the sealants I've encountered. Let them soak a while, then blow them clear with compressed air.

Always good to have a few spare cores on hand to replace those that become clogged with sealant.

Ald1 

IMHO, a good tubeless /rim setup does not need sealent to work. I would have never gone tubeless if this was the case. Ideally the sealent is only in the tire to seal flats from riding mishaps, not a poor rim seal or rim tape job.

Milton Keynes

I had the same problem with my gravel bike. I filled the tube with green slime sealant just to protect against whatever I might encounter on gravel roads. I tried to put air in the tire a few weeks ago and could barely air it up. Took out the valve core (Schrader style) and it was all gunked up. Put in a new one and now it works fine, I guess until it happens again. Not going to put any more green slime in my tubes because of this.

Leebo

Sealant seals all of that stuff, works well. Whatever the leak.

canklecat

Ditto, ammonia. It's the usual solvent/thinner for liquid latex, rubber, etc. Same stuff used by watercolor painters as masking fluid. Ammonia is also a good solvent for many inks, especially calligraphy and art inks. That's what I used to clean my granddad's Montblanc fountain pen and my calligraphy nibs.

c_m_shooter

I just remove the presta cores and run some hot water over them. They clean up fine.

Caliper

It doesn't seem that is the experience of most riders though. If I could run without sealant I definitely would drop that mess since I rarely get any sort of flat. My Warbird has DT Swiss rims with factory applied rim tape and Maxxis Rambler tires. When I first switched them to tubeless (they had <50 miles on them) I aired it up without sealant. They both seated and held air fine in the short term but would be flat after 24 hours. A bit of sealant fixed it up but once in a while I'll get a random slow leak. No punctures on the tire that I've ever found. Throw in a bit of sealant and it's fine, but still no signs of sealant outside the tire. I just don't quite trust the tire to hold air consistently if it were completely dry

smashndash

I do this every month or so. In about a year of using sealant, I’ve never had to throw out a valve core because it got clogged. However, I use tubes and have had to throw out tubes when they wouldn’t seal anymore, so take that with a grain of salt. I’m hoping to patch those tubes so I can use them again at some point.

Spoonrobot 

I just twist off the nut, the end of the threaded portion only has a mild peening and is overrun easy with a needlenose. Valve drops out and the core can be physically cleaned.

Caliper

Yes, it's cheap. Yes, I do now have them on my list on Amazon.

It's just the annoyance of having to replace things that shouldn't be a wear item. Honestly, it's just another annoyance and cost to tubeless. If it weren't for the lower weight and rolling resistance I would be on tubes for sure.

Ald1 

I hear you! It's been quite a learning curve for me but my combination of ENVE wheels and Pro One tires seal fine without the sealant and hold air just fine. As I mentioned before, I feel this is what the manufacturers need to give us. You don't need to add sealant to your "tubeless" car tires, or any other tubeless tire except bike tires to make them work right? As someone pointed out it's no big deal for them to have sealant make tubeless work. That's OK too. In my four letter adventures of learning tubeless I would always use water to see where the leaks occurred. In most cases it was spoke holes and or valve stem due to poor tape or poor tape job. It's best to heat something and melt a small hole through the tape to install the valve stem. If you do not see any leaks and you need to add sealant you might find it's going into your rim via the spoke holes. Yes in most cases sealant can cure this but I found it much harder to clean up when retaping as gunk egresses into the spoke hole etc. Rim/wheel leaks were more rare, again due to poor prep/cleaning. BTW I could NOT stop rim tape leaks with some tapes and found ENVE tape the best and easiest to use.

Ald1 

Hey Rollercam. Think you misunderstood me. To clarify, I DO run my tubeless with sealant. I add it when I'm sure I do not need it to mount the tire without leaks than add it for what it's designed for...that is sealing punctures of the tires. Just think a tubeless tire/rim combo should not relay on it not to leak.

Caliper

Except that for some of us, the sealant is more of a liability than a benefit. I rarely get flats on my bikes with tubes. I certainly have never gotten a flat that I can remember on the dirt roads where I usually ride. What I do like to do is experiment with different tires and sealant makes that a royal PITA. Want to switch tires to try something out for a few rides? You're either trashing a bunch of sealant or trying to pour it from one tire to another and either way you're sure to have a mess to clean up afterwards. Tires need to be somewhat tubeless ready and hopefully agree with your tire/rim/rim tape combo or you're resorting to an air compressor to seat the bead. I wish I could ditch the sealant because since I have switched two bikes to tubeless, I have spent more time and money messing with sealant and other tubeless stuff than I ever have spent changing flats. I like the lighter weight and less rolling resistance of tubeless, but the sealant is what always makes me question the whole proposition.