problem with corkcoasters

Hey everyone,

i got the old engravinglaser from a friend of mine, and i started to engrave some coasters.

I am very happy how they turned out for the first batch, but i have a problem with the soot thats still in the coaster, i clean out most of it with a 4 bar compressor. But once they get a little wet it spreads end ruins the whole estetic. Does anyone know of a solution for that problem? I know there are some etsy stores selling stuff like that and i am pretty sure they have a solution for that.

Thanks in advance for any help.

https://preview.redd.it/5xszu4n2iy6f1.jpg?width=3000&format=pjpg&auto=webp&s=98de86e8ed1ac83e2b2029358f38005a616981e7