Skeptical archaeologists[who?] see the electrical experiments as embodying a key problem with experimental archaeology, saying that such experiments can only show that something was physically possible, but do not confirm that it actually occurred. Further, there are many difficulties with the interpretation of these artifacts as galvanic cells:[citation needed]
The bitumen completely covers the copper cylinder, electrically insulating it, so no current can be drawn without modifying the design.
There are no wires or conductors with them.
No electrical equipment is associated with them.
A bitumen seal, being thermoplastic, is excellent for forming a hermetic seal for long-term storage. It would be extremely inconvenient, however, for a galvanic cell, which would require frequent topping up of the electrolyte (if they were intended for extended use).
The artifacts strongly resemble another type of object with a known purpose – storage vessels for sacred scrolls from nearby Seleucia on the Tigris. Those vessels do not have the outermost clay jar, but are otherwise almost identical. Since it is claimed[by whom?] these vessels were exposed to the elements, it is possible[opinion] that any papyrus or parchment inside had completely rotted away, perhaps leaving a trace of slightly acidic organic residue.