Jeppo the grip frame, mag well, backstrap under the grips, grips, grip screws, sear and sear pin are what took the most time to clean. The frame had black marks under the trigger guard and dustcover. They took a bit of time to clean too. But they came off.
Im pretty sure it was not dried coffee and powdered sugar, but it was a finegrime that adhered to......well....everything. And I found shavings and tiny pieces of that cheap "pleather" that Safariland use to use in the late 80s and 90s on their LE holsters. Well, they used it till agencies stopped buying them.
Someone wanted to see pics. Here they are. It is wearing the rounded TSW mag baseplate as that is the one that works for pocket carry, for me. The finger lift mag snagging on the draw. Again, for me. Regards 18DAI