I've seen the Natural Sea Sponge suggestion before in the forum and have concerns.
I was in my teens with my 1st car back in the 70's (71 Charger).
What I didn't know at the time was the amount of embedded sea material (shells) within the pores of the Sponge.
I did eventually learn but it was to late as the paint took a beating.
A magnifying glass easily reveals the natural embedded material (what you see laying face down on your favorite beach).
So what is different today?
I did a google search and found a Sponge Company that sells a premium Sponge dedicated to the auto detailing field.
They claim to "expertly process" this one particular Sponge on the FAQ's page.
I did not read or see details about this process.
The item page still shows a "contains sea minerals" icon. So I have concerns.
AG sells a premium Natural Sea Sponge..."a rigorous cleaning process"
Does anyone sell a guaranteed debris free Sea Sponge? I don't know and am willing to learn.
Anyway the message here is a warning using just any Sea Sponge off the shelf from the local paint store on a gloss surface.
You are correct that you should always wash your wool sea sponge out well before use. not sure if anybody sells one that is guaranteed to be free of debris.