If it is: Out of date, or old (opened more than 30 days ago) or exposed to the wrong conditions such as heat, freezing, sunlight - it is possible that it will be denatured and not work properly. Try a new bottle or pen and see if there's a difference.
Answered 8/8/2013
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A doctor has provided 1 answer
A doctor has provided 1 answer
A doctor has provided 1 answer
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