Закройте раздел цитатой и объедините последующие цитируемые разделы до конца.
Range("C8:D38,H8:I38,M8:N38,R8:S38,W8:X38,AB8:AC38,AG8:AH38,AL8:AM38," & _
"AQ8:AR38,AV8:AW38,BA8:BB38,BF8:BG38,BK8:BL38,BP8:BQ38,BU8:BV38," & _
"BZ8:CA38,CE8:CF38,CJ8:CK38,CO8:CP38,CT8:CU38,CY8:CZ38,DD8:DE38").ClearContents
Альтернатива:
dim rng as range, i as long
set rng = Range("C8:D38")
for i = 8 to 108 step 5
set rng = union(rng, cells(8, i).resize(31, 2))
next i
debug.print rng.address(0, 0)