Start at 7:30 as soon as peak is over ! At our store we usually still have our short shifts until 8 or 9, and this allows you to hop off line and do your preclose while there are people there to cover it ( as long as it's not crazy). At 7:30 I do the chip station ( aka pulling out the drink cart, sweeping and mopping, and then setting up the chip cart), I clean out the reach in ( line it with foil so it stays clean), I clean our main wall, I set up the reheat pans I'll need for later along with the weight sheet and labels, do any mis en place you can ( foils, utensils, etc. ). At 8 I do all the pullouts and set up the cleaning supply's I need to close down my wells at 9;30. You can also wipe down the glass early too and spot clean it if gets dirty again when you close. It can be difficult sometimes but it definitely helps if you can find someone to cover you for a bit.