My house was built in the 40's and evidentally back then, the owner wanted to hang shelving, they drilled 1"+ holes, inserted wood plugs and nailed into the plug. Now I have these holes, some still have the wood plugs. When I tried to remove the wood it came apart and fell back into the block. How and what materials should I use to fill these holes, I have several. I have read about repairing cracks, can I use the same type of patch??? Thanks in advance.