Yes to both above answers …. you can salvage it if you want to devote the time and trash can space…
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How much salt are we talking about in the bucket?
Anyway, I’ve salvaged “bricks” of Instant ocean:
Get a new or clean 32g trash, and “to a point” you can use/pour hot water over it; “hot” being relative…not boiling
(mind you this assumes applying common sense with hot water and a plastic trash can) ….
I would try to dump it out and break off chunks with a hammer & screw driver, and process manageable smaller chunks at a time
You might need a 2nd trash to process more salt can as it gets harder to dissolve as the water gets saltier….
if smaller chunks remain, dilute the water a lil more and run a powerhead ….the remaining chunks will get smaller over time, assuming 45< >35ppt