If you can remove the innards of the
mod and leave only the tube then brake cleaner might/should do it. So might coke, pepsi, monster, or any other heavy citrus energy drink. I used brake cleaner on a whole k100 i desleeved and the chrome wiped off but left the ?nickle? primer coating and completely destroyed the rubber gasket on the positive pin. $21 loss and leason learned. I only mention this if you can remove the innards. I dont think you can but i say it just to fill space apparently.
My second k100 i just took a dremel to it to remove the chrome and the ?nickle? coating down to the brass. I'm not in the process of sanding it going up and up in grit. It's looking pretty good and all for a mod i dont like anymore.