If you're planning to seal dozens of invitations - then using a sealing wax glue gun with sealing wax sticks is the quickest - cleanest and most efficient method.
GLUE GUN SEALING WAX
Dark Green Sealing Wax Sticks
Wedding Love Wax Stickers - Custom Wax N Seals
Package: 12 sticks in gorgeous packing (Color: Brass, Excellent color, good print looking), one pack to make more than 200 wax seals, 13-17 wax seals
Brass Gold Vintage Flexible Glue Gun Sealing Wax for Postage Letter - 5.4(L) - 12 Sticks
DIY Glitter Metallic Flake Self Adhesive Wax Seals — Wine & Sprinkles
Shop Wax Seal Stamp Gold with great discounts and prices online
Floral Crest Wax Seal – Written Word Calligraphy and Design
Written Word Calligraphy - Glue Gun Sealing Wax (Box of 5 Sticks
How to Make Wax Seals