First thing to do is to check the type of leather you have. Sticky areas after this length of time may be an indication of Bicast leather. If this is the case and it hasn't been protected on a regular basis then body oils could have broken down the coating.
If it is not Bicast but a standard protected leather then there would appear to be a problem with the finish or a build up of grease.
Foam cleaning would be a good start and then see what you are left with.
Using cream cleaners is a real problem and 'conditioners' will only add to it.
This doesn't sound as though it is a 'cleaning' problem and may not be resolved this way. Joe will tell you all about this!!!!!!!
If we can be of further help please do not hesitate to contact us
I was at the NCCA Technical Roadshow on Tuesday at Shrewsbury with about another 25 carpet cleaners from as far away as Fort William and London.
Andy and Judy from LTT were there doing a presentation, and we covered sticky surfaces on Bicast.
Strange how things come about - 2 days ago on a training session, then it gets mentioned.
For £25 (£35 for non NCCA members and buffet included) that was a very good day.
Going off topic (apologies) but Host were there, and they have a new Reliance CRB (counter rotating brush) system launched at a special price of £999 inc vat and a set of brushes of your choice.