(Seam Sealer from the drip rails, not body filler! Sorry!)

What would I use to soften the hardened seam sealer in the drip rail? (no sand blasting)
I removed the drip rail trim and the majority of the seam sealer from the bottom of the drip rail mounts. But the outer mounts (on the car) seem to fold backwards, creating a type of 'C' shape that has a lot of hardened seam sealer still stuck in it. I started using a thin small screwdriver to scrape it out, placing the handle against the hood, the point under the lip. The only thing I am afraid of is changing the shape of the mount so my old rail trim won't go on smoothly.
Is there a chemical that will soften it (mine is hardened cement in some areas). Or will working it with paint remover and the rust remover take the remainder of it out? Or use a hook shaped tool and keep scraping?
One last question, I apply primer first, then the new seam sealer? I am using a caulking gun to apply the sealer. Do I use anything to press/force it into tiny crevices and spread it evenly or will it "flow' on it's own?
Thanks all!

 

Paint stripper will get it out, but its caustic, messy, and you still end up digging it out with a chisel or screwdriver. I prefer to scrape it out with some thing that fits in the gap, or use a wire wheel on an angle grinder. With the wire wheel you have to be careful not to remove metal, it can deform drip rails or other parts VERY easy. Old filler can be rock like as you know, but its softer than the metal so just avoid bending or warping the metal and dig it out. Not fun but part of the DIY thing.

What kind of filler are you using? The filler I use is a two part system with a hardener, its pretty much standard for body work. As for filler and primer, I do both. Large areas like the quarter panel seams on the PoD get it over bare metal, but it isnt finished at that point. I then apply primer over the filler and find the low spots, fill those and sand them smooth. When I am applying filler over bare metal I use an angle grinder to roughen the surface to give the filler something to bite so to speak. You can see what I mean in this pic. Be careful not to over heat or grind the metal away, just rough it with a light pass.

 

I went back and corrected my message after reading your reply. I am using 3M's Seam Sealer ( I think 8050?), not body filler as I had mentioned in my original post. I keep forgetting they are not the same thing!
As I take out the original SEAM SEALER from the drip rails, it appears that was applied direct to the metal and then had the primer applied over it. It should work well over epoxy primer since you do put it over paint as well?
I plan to work phosphoric acid in with a wire brush to clear up any remaining rust and prep the metal for paint, so hopefully that will help remove the remnants of filler. I was hoping to get it all out, so I could work on rust alone.