I got a lot of tree sap drips on my rain fly during my last outing, read some of the threads in this forum, but emailed Hennessey to get their recommendations. Here is their reply. Figured I'd pass it along for reference:
"I have had good results using a citrus or pine oil based turpentine which seems to work well at dissolving the sap without also dissolving the plastic fibres. The waterproof coating is silicone I believe, which should be impervious to this. Mineral turpentine is NOT recommended however.
Any turpentine residue can be gently washed off with a mild detergent.
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