I agree. That’s why I said to put the IPA in the sun for a while before straining it.
I doubt there’s any practical way to get 100% of the resin out of the IPA. But far worse than a bit of cured resin mixed with IPA goes down domestic drains every day (read the MSDS on the Resin, it’s surprisingly “benign”). The IPA component doesn’t matter anyway, you’re allowed to put that down the drain. And I figure treatment plants ought to be able to filter out any remaining resin just like they filter out fine organic particulates…
Some municipalities have “household chemical” disposal dropoffs. If you’re lucky enough to live somewhere that has such a service you could go there instead of pouring your IPA down the drain. The only other alternative is to pay for disposal, which can be a pain in the *ss since that’s federally regulated and there can be paperwork. Though if you’re using your FL printer in a commercial environment you might be required to do this by law anyway.