|Yes, I know it's an old Soldering Iron,|
but, it works.
And, that Critter, does not want to readily absorb water?
What a pain!
There may be a Solution.
For the last week or so, I have been experimenting with Tin Plating Methods for my Homebrew PCB Projects. For this, I have read and learned a lot of chemistry. In the Electroplating Industry, Polyethylene Glycol (PEG) is used to; slow the growth of Tin Whiskers, and to keep the new Tin Plated surface smooth and shiny. The PEG shields the sharp crystal growth points, while allowing other non-pointed areas to attract more Tin. The results is a much better, even Tin plated deposit.
I did not have PEG to use for my Homebrew plating experiments, but I had a similar material Propylene Glycol (PG) which has similar properties. I have some PEG on order, but for now PG seems to work.
But then, "While working in my Lab, late one night . . . ", I discovered a paper towel that had been previously used to wipe-up spilled PG, it had not dried! It was still moist and soft.
I remembered from my previous research, PG and PEG are used in many products in industry like; food, medical, and toothpaste. PEG and PG are used to attract and/or retain moisture (it is hygroscopic).
Maybe this is the Solution. If so, this is just exactly what my Crispy Critter (the solder-tip-cleaning-sponge) needs, I soaked the sponge in PG. So far, it seems to stay moist much longer, and it readily accepts more water (or more PG).
More (or longer) observation is clearly needed, and I will post an update later.
Polyethylene Glycol (PEG) is available on the Internet as Wood Stabilizer at 10 pounds for about $50.00, or at the Drug Store as a Laxative in 4 oz containers for about $5.00, at Costco also a Laxative.
Propylene Glycol (PG) is available at Chemical Store, or at most; Hardware, Auto, and RV Supply stores, as "pool or potable water antifreeze", this is what I used to soak my Crispy Critter.
Both are environmentally friendly and not toxic.
CAUTION, Do not confuse either of the above with Ethylene Glycol (a toxic automotive antifreeze) which ingestion can result in death.