What do you do with old uncleared transactions?

[Adam Funk]

On 2015-05-12, Maf. King wrote:

> On Tue 12 May 15 12:22:15 Adam Funk wrote:
>> Hi,
>> 
>> I have a few transactions in bank & credit card accounts that are a
>> few years old but uncleared --- a check that never got cashed, & some
>> credit card purchases that have never appeared on statements.  What do
>> the rest of you do with such things?

> In the case of an uncleared (presumably lost) cheque, I've voided the 
> transaction before now
>
> Would probably do the same with a credit card txn that never went through.  
> Deleting the tnx feels 'wrong' to me.

What are the effects of "voiding" a transaction in gnucash?  Is it
possible to un-void it, without having to keep records somewhere
else, if the cheque or credit card purchase appears on a statement
later?