Note that what is underneath these "blobs" is typically not a "full" IC, but just a chip of silicon ("bare die") bound directly to the board ("Chip on board" technology.) The blob is not just "hiding" the chip, but is the only physical protection of the chip itself and some very fragile die wires.
Thanks westfw, I don't intend to play with nitric acid but I know a few chemists hmmmmmm Dissolving because of the chip is not that interesting but a bare die... that would be a reason
"I have not failed. I've just found 10,000 ways that won't work." - Thomas Edison