Thanks folks!

No. if anything can be cleared it would have a name indicated, like "muddy scrap" in the swamp type of crypts.
Crypts are proc gen, so some can be tiny, just a room or two, others can have dozens of rooms, just a matter of luck.

The burial crypts come in all sizes and configurations... There are no situations, that I am aware of, where a pick will have any use inside the crypts.

Some crypts will contain very few cores, and have even seen people mention they have found zero cores in some crypts, while others can contain cores up into the teens (my best one had 13 cores)... Its all just a matter of RNG.

I've had zero cores from a crypt and I've had over 20 from a single crypt.
In time you will have more than you know what to do with.