Store Row Number Within Loop And Delete All Stored Rows After Loop?

I have working code that returns a row number within a for loop based on parameters I set.

Each time the for loop runs I would like to store this row number, then after the loop has finished, delete all stored rows.

Code:
for rowNum = 1 to x (some variable end row number which I already have worked out using End(xlUp).Row)
if x = y then
*storedRow = rowNum
end if
next rowNum
*

Lines with a * are the bits I can't work out. I've been trying to understand arrays by reading posts on what other people have done, but I can't fit (or fully understand) the reDims, or reDim preserves into my code. I've seen what appear to be quite complex ways involving uBounds and LBounds, but unfortunately I can't see how to use them.

All I want is to simply keep adding a row numbers to a variable, (i.e. row 2, 5, 20, 33, 120, etc) and then delete those specific rows.