old bloke who had my 110 (from new) before me took it down his local garage once every 6 months to get the chassis sprayed with the used engine oil - it's an 89 110 and the chassis is in much beter condition than many of the post 2000 models round here
just remember to get someone else to do it cos used engine oil is nasty stuff, and park on someone elses drive for 24 hours after it's done