You can find thousands of leads to buying opportunities on Ariba Discovery, which is used by Microsoft and many other Forbes Global 2000 companies. It's a powerful service to connect you with active buyers looking for the products and services your company offers.
Just go to Ariba Discovery and register as a seller. We will then send you email notifications every time there is an RFI or RFQ posting that matches your company's offering. Make sure you complete your profile as much as possible by selecting level 3 and 4 commodities (categories) - that way you won't miss out on any leads.
I suggest you consider signing up for Ariba Discovery's Advantage program, which provides you with premium marketing and sales tools and much more visibility with leading buying organizations. Plus, you can respond to eIntros, which is another form of buyer posting. I just searched for "janitorial" and there are 3 RFI/RFQ postings and 38 eIntros on Ariba Discovery.