This is the most recent thread dealing with this topic: "Soft Tissue" again
To sum up, I’d say look for whether it’s “traces of” soft tissue, which isn’t necessarily the same thing as soft tissue. (Footprints are “traces of” the creatures that made them.) Many recent discoveries have been made of casts of soft tissue, or mineralized soft tissues, where cellular structures are preserved in great detail without still being “soft,” or, most excitingly, we can now find microscopic elements of the actual biological remains inside the (mineralized) bones. Schweitzer had to dissolve her fossil bones in acid (what was she thinking!) in order to get the ‘soft, stretchy’ collagen networks that have been causing such a ruckus.
Clearly, fossils are really cool and we’re still learning a lot about them, but also clearly, all dinosaur remains are really, really old, much more decayed than mere thousands of years would account for. We find mammal remains thousands of years old with flesh still covering the bones, in certain very dry, very cold, or very anoxic circumstances, but nothing remotely like that is a dinosaur.*
*Unless it’s from the bird lineage of dinosaurs!