Are PCR reactions stable at 4 degrees?

[Harry Witchel]

Bonjour mes amis Moleculaire !
   I was wondering if anyone knew how stable PCR reactions were when 
stored in the refrigerator at 4 degrees.  I know that if I do a PCR run 
overnight and use that reaction as a template for a further reaction, I 
will get the correct product, but I seem to be getting results suggesting 
that if I take the first reaction and store it in the refrigerator for 
3-4 days (as a PCR reaction, with oil and all the reactants still in it, 
I can't do the second half of the reaction (the result is usually a 
smear with no indication of the correct band).  Does anyone else have 
experience of this problem?  Is there some way to protect the reaction 
simply (eg adding EDTA) or do I have to remove the oil and phenol 
chloroform extract every single reaction I want to reuse?
   Thanks much,
   Harry