That would be 1989, not so coincidentally Flo Jo, just 28 and with no injuries or pregnancy and at the height of her stardom, retired just days after the announcement of random testing. Also after her co-trainer, one Darrel Robinson, admitted her sold her steroids (and Carl Lewis too)
Throw out her records, they are a joke, along with Koch's joke 400m record (her name was found in East German doping logs) and a handful of others, mostly throws. A couple jumps that are also out of reach. It would only impact women's records. I think only one men's current WR was set prior to '89.
If they complain about it, then just create a separate category for pre-random testing records. Certainly random testing did not kill drug cheating, but it did eliminate it to a great extent and leveled the playing field.
I'm sure these drug cheats will have the audacity to complain.
There is a precedence for erasing the books, you can look at the introduction of FAT (Fully Automatic Timing) as it ushered in a new era in recordkeeping. Records set prior to FAT were instantly obsolete and disregarded. So you can use a similar rationale. That testing was inadequate.