First, you asked the first question on here just a few hours ago. Contributors on this page are unpaid volunteers so it cannot be expected to get an answer immediately.
However, good job clarifying your question with the image!
C = {'hello world';245;220};
isAbove230 = @(x)isnumeric(x) && x>230; % define a function to identify elements above 230
idx = cellfun(isAbove230,C); % where are they?
C(idx) = []; % remove offending elements
Or to make a copy
C230 = C(idx);
