I am doing the contour integration using Mathematica. After extraction of residues, my expression contains a lot of unwanted pairs such as

(I t - u y[2]) (I t + u y[2]) 

or

(t^2 - I u Sqrt[w[1]]) (t^2 + I u Sqrt[w[1]]).

I want them to be combined so that $i$'s should be no longer involved in the expression. Any suggestions?

I am doing the contour integration using Mathematica. After extraction of residues, my expression contains a lot of unwanted pairs such as

(I t - u y[2]) (I t + u y[2]) 

or

(t^2 - I u Sqrt[w[1]]) (t^2 + I u Sqrt[w[1]]).

I want them to be combined so that $i$'s should be no longer involved in the expression. Any suggestions?

added: Maybe I should write down the (part of) real example which I want to reduce.

Simplify[((I Sqrt[t/u] - y[1]) (I Sqrt[t/u] + y[1]) (-1 + 
  I Sqrt[t/u] y[1]) (1 + I Sqrt[t/u] y[1]) (1 + 
  y[1]^2) (I Sqrt[t/u] - y[2]) (I Sqrt[t/u] + y[2]) (-1 + 
  I Sqrt[t/u] y[2]) (1 + I Sqrt[t/u] y[2]) (1 + 
  y[2]^2) (I Sqrt[t/u] - y[3]) (I Sqrt[t/u] + y[3]) (-1 + 
  I Sqrt[t/u] y[3]) (1 + I Sqrt[t/u] y[3]) (1 + 
  y[3]^2) (I Sqrt[t/u] - y[4]) (I Sqrt[t/u] + y[4]) (-1 + 
  I Sqrt[t/u] y[4]) (1 + I Sqrt[t/u] y[4]) (1 + 
  y[4]^2) (I Sqrt[t/u] - y[5]) (I Sqrt[t/u] + y[5]) (-1 + 
  I Sqrt[t/u] y[5]) (1 + I Sqrt[t/u] y[5]) (1 + 
  y[5]^2) (I Sqrt[t/u] - y[6]) (I Sqrt[t/u] + y[6]) (-1 + 
  I Sqrt[t/u] y[6]) (1 + I Sqrt[t/u] y[6]) (1 + 
  y[6]^2))/(2  (-I Sqrt[t/u] + t Sqrt[w[1]]) (I Sqrt[t/u] + 
  t Sqrt[w[1]]) (t^2 + w[1]) (1 + t^2 w[1]) (Sqrt[u] - 
  I Sqrt[t^3 w[1]]) (Sqrt[u] + I Sqrt[t^3 w[1]]) (-I t + Sqrt[(
  t w[1])/u]) (I t + Sqrt[(t w[1])/u]) (t^(3/2) - 
  I Sqrt[u w[1]]) (t^(3/2) + I Sqrt[u w[1]]))]