As Rich Gilson excavated debris around his house in Wildwood Friday, he didn’t initially realize that he had just unearthed a Jersey Shore mystery – tightly-wound $10 and $20 bills totaling about $1,000 that may have been buried for up to 90 years. Gilson and his wife, Suzanne, bought the 1920s-era cottage on West Andrews Avenue about four years ago. They elevated the house, added a new foundation and an addition. Using a rented mini-excavator, Rich Gilson encountered plenty of rocks and parts of the old foundation as he worked on Friday. Then he spotted two “little round things” maybe 2 inche…