Removing Seam Sealer from Silnylon Tarp

how about rubbing it off? with your fingers?

If it's rolled on thick silicon, it should roll off fairly easily (MLD recommends a fairly decent coat of the stuff and I found excess was easy to just grab and twist). Tarptent has users seam seal theirs with a mixture of silicon and mineral spirits, so assuming the latter is ok to use (may want to test out first on a non-critical seam).

Sounds like that Seam Grip was used .
If this is the case ,try rubbing alcohol.
That should soften the glue and you then you should be able to peel it or gently scrape it off.
A few years ago I removed a layer of the wrong type silicone applied to a tarp by using mineral spirit (cloth impregnated with…) and then scraping that off with a sharp blade.
Obviously if you use a blade next to fabric there is a chance of cutting the fabric….

Wow, thanks everyone for your responses. I've tried rolling it off with my fingers and rubbing alcohol. Mineral spirits are next on the list.

Now, for another question – spot seal or reseal over the old seal?