Usually I put canister of silica gel or strips of vapor corrosion inhibitor in my cupboard (that contains many metal repair tools) to absorb moisture so that I keep the rust at bay.

So, How do I know if the canister of silica gel or strips of vapor corrosion inhibitor have lose its effectiveness in absorb moisture? (so that I can replace them with new ones. or do they really last a lifetime?)

1 Answer 1


Silica Gel often has a color indicator, either going from blue(dry) to pink(wet), or from orange(dry) to green(wet). By heating the gel to 250 °F for 2 hours, you can restore the gel to its dry state and reuse it.

  • 1
    Make sure it's in an appropriate container before you put it in the oven - ie: not in plastic or paper
    – Steven
    Mar 6, 2012 at 13:29
  • Never thought that I can heat the gel at 121 °C (or 250 °F) to restore the gel. Good.
    – Jack
    Mar 7, 2012 at 1:17
  • Also, by the way, I have a Gel of white color. Is it dry or wet? Also, I have another Gel of cyan color, can I consider it as blue color?
    – Jack
    Mar 7, 2012 at 1:19
  • Also, is it possible to heat the strips of vapor corrosion inhibitor like the way we heat the gel to restore it to its dry state?
    – Jack
    Mar 7, 2012 at 1:20
  • @Jack The color is from an added chemical. I think the Gel defaults to white and doesn't change by itself, so the white may be some Gel without a color indicator. I don't think there's any harm in restoring it prematurely if you're not sure. No idea on the vapor strips.
    – BMitch
    Mar 7, 2012 at 2:57

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