PART L - PATCHING AND CLEANING
Be careful not to smear mortar on the blocks. Once it has hardened, you cannot remove it, and paint will
not always hide the smear. If you drop any mortar while laying the blocks, let it dry exactly as it falls
and then try to remove it by striking it with a small piece of broken concrete block (Figure 2-34)
Concrete-block was should never be cleaned with acid. If you need to patch mortar joints or fill holes
left by nails or line pins, always use fresh mortar.
Figure 2-34. Removing dried mortar with a piece of broken block